Azzi's Blog

Why is My Computer So Slow? Four Possible Reasons

2008-04-16T03:30:00.002-07:00

Today's computers have faster microprocessors, more memory and bigger hard drives. When you think about the differences between a Pentium 4 and 386, you have to conclude the improvement is astounding! So, why are so many of these modern day miracles running way below their potential?

In this article we will discuss four very common but often overlooked reasons why that rabbit in your PC has turned into a snail and we'll tell you what can be done to get it back up to speed.

You need more memory.

Don't overlook the obvious. Up until recently not having enough memory wasn't a problem. With the price of RAM becoming very affordable, most people were filling their computers with more than enough memory to do the job. Enter Windows Vista! Many computers built to an older spec were loaded with Vista and put on the market.

When the new owner got the computer home and took it for its first joyride it just didn't live up to expectations. The reason for this is, Vista is a resource hog. Many computers now come out of the box with Vista and 512MB of memory. With Vista you need at least 1GB of Ram. If your computer is slow and it has Vista with 512 MB of Ram you need to add more memory.

Spyware and viruses

Speaking of resource hogs. Spyware and viruses steal a lot of your computer's resources. Though it is not their main function to just make your computer run slowly, these programs can bring your computer to a screeching halt.

Of course, you do have a good Spyware/Virus remover. Don't you? Also, you do realize for them to be effective, you have to keep up to date. By up to date, it means up to the minute.

You should have your remover program set to update and run automatically overnight or at some other time you don't regularly use your computer. If you don't, spyware and viruses will eat your computer alive! Slowing down is nothing compared to what could happen to your computer's resources if you don't have a good remover program you update and run daily.

Background programs

When you install new software on your computer, often times you install it to run in the background every time you start up. Most times you do this without knowing it. Look at the bottom right hand side of your screen.

If you see several icons there, you have extra programs running and stealing resources. Right click on these and see if you have the option of closing them. Many times, you can open the program and choose an option to keep these programs from starting automatically. Many times I've seen this move get a PC back to its old fleet footed self.

Corrupted registry

Here's one problem that is mostly overlooked. Any changes you make to your computer effects and actually, corrupts your registry. So, it stands to reason, even when you do something positive; like remove spyware, you end up with a corrupted registry.

After months of corrupting your registry, albeit unintentionally, it will become good and out of whack. This will, in its early stages, cause your computer to slow down. In its advanced stages, it will freeze and crash and do more mysterious and troublesome things.

Many times, I hear people say they have scanned for spyware and viruses and found none, but still the computer runs very slowly. Most times, it isn't until the registry is cleaned out and repaired by a top-notch registry cleaner that the computer's speed is restored. Make sure to run a good registry cleaner every week or so to keep your registry in excellent working order. After all, the registry is what your operating system is made of.

So there you have it. To recap:

512MB is usually enough for Windows XP but not Vista.
Keep your computer free of spyware and viruses.
Don't let too many programs start automatically, and
Run a good registry cleaner often.

Danger - The Hidden Costs of Spyware

2008-04-16T03:30:00.001-07:00

Unwanted spyware running on your system can be a huge and unnecessary hassle. While the most obvious problems associated with spyware are popup windows and a slow computer, there are hidden costs that many people don't consider. Spyware can cause a huge drain on your time, money, and computer enjoyment. Let's explore some of these issues and find out what you can do to be spyware free and avoid these hidden costs.

Time

The number one hidden cost of spyware is your time. Leaving spyware unchecked on your system will only result in things getting worse as time goes on. In most cases, the worse a spyware problem is, the longer it is going to take for you to figure out what is going on and how to fix it. Like most users, you're going to be spending time searching the internet for solutions to your problems. Checking message boards, reading articles, and doing general research to figure out how to remove your spyware takes up a huge amount of time that most people don't take into consideration. Then when you find out what spyware is infecting your PC, it takes time to actually remove the spyware itself. This can sometimes consist of very long scan times and multiple reboots. If you put any value on your time, this brings us to our next item...

Money

For many people such as office workers and freelancers, the computer is directly tied to their income and spyware can deeply affect them in the pocketbook. From a slow and sluggish computer to loss of valuable work hours trying to fix the problem, unwanted spyware is causing you to waste time, work less productively and in the end is costing you money. If left unchecked, the spyware problem may get so great that you need to take your computer in for some professional help. Unfortunately most of these computer repair places charge enormous hourly rates and try to sell you repairs or upgrades that you don't even need. In some cases the cost can be so high that it would be cheaper for you to just buy a new PC! Besides being expensive, this can be very frustrating and leads to a loss of...

Enjoyment

What's the point of using your computer if you don't even enjoy it anymore! After one bad encounter with spyware, many people can be put off or even scared to use their computer in fear of it becoming infected again. Browsing the internet and using your computer should be a fun & educational experience. Dealing with popup windows, rogue toolbars, and unwanted software can really put a damper on things. Fortunately there is an easy way to avoid all of these issues...

Protect Yourself

Use an anti-spyware or spyware removal program regularly. Many programs can be downloaded for free and will let you scan your PC to see if you have any spyware running on your system. Regular spyware scanning and removal will keep your computer running in top shape and will help you avoid all of the hidden costs that you may face down the road.

Happy and safe computing!

Charlie K is an anti-spyware advocate and teaches others how to keep their computers running spyware free. Learn more about spyware removal programs and how to protect yourself online by visiting his website http://www.becausespywaresucks.com.

Article Source: http://EzineArticles.com/?expert=Charlie_K

How To Connect Your Computer To Your Home Theater

2008-04-16T03:29:00.002-07:00

These days, a computer can act a lot more like an entertainment device than ever before. You can watch online video, listen to music, view pictures and more!

But who wants to sit in their home office on a desktop computer or sit at a notebook computer to do this? "Not I, said the cat." Listening through cheap computer speakers and watching video on a computer monitor is not my idea of real entertainment; how about you?

Why not connect your computer's audio and video to your home entertainment system? You can watch TV shows, movies, and videos on your HDTV or any other TV with appropriate inputs. You can listen to music through your home stereo if it has AUX, VIDEO, or any other input using a standard RCA connection.

Connecting Computer Video to Your TV:

To connect the video, your computer must have an output for which your TV has a matching input.

Virtually every computer comes with a VGA output of some kind. The plug for this looks almost rectangular (you can see one by locating where you computer monitor connects to the back end of your desktop computer).

Another video output connection many computers may have is S-Video. This is a round connection. S-Video plugs have 4 tiny round holes (2 on each side) and a tiny rectangular hole in the bottom. S-Video cables have a round end with 4 tiny metal prongs and a tiny rectangular piece of plastic at the bottom.

However, many televisions do not have VGA inputs and only some have S-Video inputs. If yours doesn't, you'll need to make sure it at least has an RCA video input (this is a very standard connection which is used to connect record players, VCRs and CD players to other devices). If your TV came out since the early to mid 1990s it most likely has a standard RCA video input.

If your TV does have an RCA video input, simply buy a VGA to TV Converter. This will connect to your computer's VGA output and provide RCA and S-Video connections (which are standard inputs found on most TVs since the 1990s).

Make sure you have the proper cables for your TV. Depending on which type of input your TV uses, you'll need an RCA cable, an S-Video cable or a VGA cable.

Connecting Computer Sound to Your TV, Stereo or Home Theater System:

Now that the hard part is out of the way, the sound is easy. Simply buy a Y-cord. It should contain a stereo male 1/8" on one end and two RCA males on the other end. Just ask your local electronics store; this is a standard cable they will all most-likely carry in-stock.

Connect the stereo 1/8" male end to the green jack on your computer (usually on the back of desktop computers and on the front or side of notebook computers) where your speakers would normally connect.

Alternatively, you may connect the 1/8" to the headphone jack on your computer. (Note: any device with a headphone jack can connect to your home theater, such as an iPod using this same cord!)

Connect the two RCA males to the L and R input jacks on your TV, Home Theater or Stereo. And you're done! Just make sure to select the right setting (AUX, VIDEO, etc.) on your stereo or receiver.

Enjoy online content in all the glory you've enjoyed content from TV, DVD, CD, and the radio! There's already tons of online content available on major broadcasting sites, and there will be more as the future moves forward.

If you don't have a DVD player but there is a DVD drive on your computer, this setup will turn your computer into a DVD player! Once connected, call the store from whom you bought your computer and ask how to play a DVD on the computer.

The author would like you to visit CISSP, ISO/IEC 27001, DoD 8570, Information Security Training, Philadelphia Center and Register: CISSP & ISO/IEC 2700 Training: Philadelphia, New Jersey, Washington DC

Article Source: http://EzineArticles.com/?expert=Gabriel_J._Adams

Connect Your Computer To Your Xbox 360 Using Winamp Remote, Windows Media Player 11, or a Windows ME

2008-04-16T03:29:00.001-07:00

Your Xbox 360 is an amazing piece of technology, it can play the latest games, and movies in HD, play your favorite songs from it's hard drive, download updates over the internet when it's on and off. The amount of things you can do with it is probably endless, well, endless unless Microsoft legally restricts it, like they did with mod chips. With new software coming out to support your Xbox 360 you can now connect it to your PC and stream all your music and videos from there, rather than wasting your precious hard drive space on your 360. Some software even lets you stream videos from internet sites like YouTube and AOL. If you want to do this you have three options for streaming to your Xbox 360: Windows Media Player 11, WinAmp Remote, or by using your Windows Media Center PC.

Using Windows Media Player 11

First make sure your Xbox 360 is connected to the network and can connect to Xbox Live.
Open up Windows Media Player 11, and click on the arrow directly below the Library tab, then click on Media Sharing.
A Media Sharing Window will popup, now check the "Share my media to:" box and click on your Xbox 360. Select allow and click okay.
Wait a little bit. You'll have to wait for the system settings to take effect and for the Xbox to show up in the network, if you've waited and nothing's happening try redoing the process or opening up the ports on your router for the 360 (a good place to do that is Port Forward) because they could be blocking it, and also make sure there isn't a firewall enabled somewhere that is causing problems.
After you've waited, get on your Xbox and select the Media blade, then Music or Videos, and then press X to change your source and select your computer.
Everything you have in your library will show up on your 360 now. Enjoy your songs and videos.

WinAmp

Download and Install WinAmp Remote.
Right click the WinAmp Remote icon in the system tray, click configure, and then media tab.
Add the folders that contain your music and your video files.
Again, you'll need to wait a little bit for the network to show up with the 360.
Go to your Media blade on your Xbox 360 and press X to change the source and select your PC.
Enjoy your media.

Windows Media Center PC

Go to www.xbox.com/pcsetup to download the necessary software updates for your PC.
On your Xbox 360 go to the Media lade, select Windows Media Center, and follow the easy, on screen instructions to complete your setup.

Each of these options are very easy to implement, and have different pros and cons. Currently, Windows Media Player is faster at streaming and buffering than WinAmp Remote, and it seems like it is more stable, but WinAmp Remote has the ability to stream online videos. And the Windows Media Center PC option is perfect if you have a Media Center PC.

Steve's Tech Guide - A blog that helps you scratch your tech itch with computer guides, informative how-tos, and important news events.

Article Source: http://EzineArticles.com/?expert=Steven_Stoddard

Four Gadgets You Wish You Had

2008-04-16T03:28:00.000-07:00

Get it? Wave? Future? Hahaha! C'mon, work with me here.

I watched a James Bond movie lately and I thought of something. James Bond always has these cool gadgets to help him out, invented by Q. Pen guns, flying cars, rocket guns, everything he needs. And futuristic movies I've seen always have cool stuff that people supposedly invented. So I've put together my list of futuristic gadgets that I would love to have.

1. Time Machine - Who wouldn't want a time machine? You can go back in time to see the dinosaurs up close (just not too close)! You could see Rome and Greece in all their past glory. Maybe even see the legendary Spartans, just to compare them to the ones in 300. Or you could use it to go back to yesterday and give your mother a present for the birthday you forgot, jerk. I wouldn't mind having one, even if it was made out of a DeLorean. Many scientists say that it is truly impossible to travel to the past and the laws of physics only allow travel to the future, but who knows? Mankind always finds a way!

2. Virtual Reality - This already exists in some form, but what I want is full-on perfect virtual reality! Just put on a helmet or glasses and you just think what you want to do, and your virtual self will do it! You can even smell scents and actually feel what you touch in that world! It would be great for the date scene since you get to date without actually being there, or you can talk and hug your loved ones from far away. You can even be the star of your own virtual adventure movie! The possibilities are endless!

3. Teleporter - I think anyone can use this. Why take the bus to work when you can just teleport there? You can even work overseas while still living in your own house! Take your time in the mornings since it's hard to be late for work if you can get there instantly. You can even take your lunch break in Paris and come back in time for the afternoon meeting! Too bad this may never happen, because there's always a chance that not all of your body parts arrive at your destination. But like I said, who knows?

4. Electronic Contact Lenses - I saw this in a movie once. You wear contact lenses that display data right in front of you. No more checking your watch for time when all you need to do is look at the digital clock in your vision! You can even have your daily planner displayed there, or even view videos or surf the net! All you have to do is think what you want to see and it'll pop up.

There you have it. Science just keeps moving forward, and one day all these gadgets may as well be real! Having gadgets makes people lazy though, but we can probably invent auto-exercise machines for that. ;) How about you? What gadgets would you like to have?

Ted is a prolific travel writer who has the amazing ability to draw out the real stories from each and every city he visits.

Browse his blog at Blue Wave Ted

Article Source: http://EzineArticles.com/?expert=Ted_Hill

Interview questions on Fiber Channel & Storage Technology

2008-04-16T03:00:00.002-07:00

1.WHAT ARE THE BENEFITS OF FIBRE CHANNEL SANS?

Fibre Channel SANs are the de facto standard for storage networking in the corporate data center because they provide exceptional reliability, scalability, consolidation, and performance. Fibre Channel SANs provide significant advantages over direct-attached storage through improved storage utilization, higher data availability, reduced management costs, and highly scalable capacity and performance.

2.WHAT ENVIRONMENT IS MOST SUITABLE FOR FIBRE CHANNEL SANS?

Typically, Fibre Channel SANs are most suitable for large data centers running business-critical data, as well as applications that require high-bandwidth performance such as medical imaging, streaming media, and large databases. Fibre Channel SAN solutions can easily scale to meet the most demanding performance and availability requirements.

3.WHAT CUSTOMER PROBLEMS DO FIBRE CHANNEL SANS SOLVE?

The increased performance of Fibre Channel enables a highly effective backup and recovery approach, including LAN-free and server-free backup models. The result is a faster, more scalable, and more reliable backup and recovery solution. By providing flexible connectivity options and resource sharing, Fibre Channel SANs also greatly reduce the number of physical devices and disparate systems that must be purchased and managed, which can dramatically lower capital expenditures. Heterogeneous SAN management provides a single point of control for all devices on the SAN, lowering costs and freeing personnel to do other tasks.

4.HOW LONG HAS FIBRE CHANNEL BEEN AROUND?

Development started in 1988, ANSI standard approval occurred in 1994, and large deployments began in 1998. Fibre Channel is a mature, safe, and widely deployed solution for high-speed (1Gb, 2Gb, 4Gb) communications and is the foundation for the majority of SAN installations throughout the world.

5.WHAT IS THE FUTURE OF FIBRE CHANNEL SANS?

Fibre Channel is a well-established, widely deployed technology with a proven track record and a very large installed base, particularly in highperformance, business-critical data center environments. Fibre Channel SANs continue to grow and will be enhanced for a long time to come.The reduced costs of Fibre Channel components, the availability of SAN kits, and the next generation of Fibre Channel (4Gb) are helping to fuel that growth. In addition, the Fibre Channel roadmap includes plans to double performance every three years

6.WHAT ARE THE BENEFITS OF 4GB FIBRE CHANNEL?

Benefits include twice the performance with little or no price increase, investment protection with backward compatibility to 2Gb, higher reliability due to fewer SAN components (switch and HBA ports) required, and the ability to replicate, back up, and restore data more quickly. 4Gb Fibre Channel systems are ideally suited for applications that need to quickly transfer large amounts of data such as remote replication across a SAN, streaming video on demand, modeling and rendering, and large databases. 4Gb technology is shipping today.

7.HOW IS FIBRE CHANNEL DIFFERENT FROM ISCSI?

Fibre Channel and iSCSI each have a distinct place in the IT infrastructure as SAN alternatives to DAS. Fibre Channel generally provides high performance and high availability for business-critical applications, usually in the corporate data center. In contrast, iSCSI is generally used to provide SANs for business applications in smaller regional or departmental data centers.

8.WHEN SHOULD I DEPLOY FIBRE CHANNEL INSTEAD OF ISCSI?

For environments consisting of high-end servers that require high bandwidth or data center environments with business-critical data, Fibre Channel is a better fit than iSCSI. For environments consisting of many midrange or low-end servers, an IP SAN solution often delivers the most appropriate price/performance.

Network Attached Storage Introduction

2008-04-16T03:00:00.001-07:00

What is NAS (Network Attached Storage)

In a NAS architecture, corporate information resides in a storage system that is attached to a dedicated server, which in turn is directly connected to a network, and uses a common communications protocol, such as TCP/IP. In a corporate IT infrastructure, the NAS operates as a server in a typical client/server environment. The NAS is connected to a network by standard connectivity options such as Ethernet, FDDI and ATM. In some cases, a single specialized NAS server can have up to 30 Ethernet connections.

A NAS server (a processor with an operating system) is necessary in order to transfer the data between it and the NAS storage device, and then move the data on to the corporate network. This is done via traditional file I/O protocol. The most common of these protocols are Network File System (NFS) and Common Internet File Service (CIFS).

NFS was originally developed by Sun Microsystems and is now part of the Open Network Computing (ONC) initiative. It is the most common file access protocol to access shared files in a UNIX environment. CIFS is a file access protocol designed for the Internet, and based on the Server Message Block (SMB) protocol used by the Microsoft Windows operating system. CIFS does not replace the use of NFS, but rather complements it, because of its ability to provide synchronization between client and server.

Although a NAS with NFS can be implemented on readily available tightly-coupled server and disk storage arrays, there are actually only three (3) major vendors that currently have a large marketshare of the NAS marketspace. They are: Network Appliance (also known as NetApps), Auspex Systems, and Sun Microsystems. Both NetApps and Auspex use proprietary tightly integrated servers and storage devices. In the majority of cases, the Sun implementation uses a dedicated Sun server, and typically connected to external Sun storage; although any external storage that is certified to be connected to a Sun server can also be used. However, this is not the case with NetApps or Auspex, as additional storage requirements must be acquired from the respective NAS vendor.

The NAS server permits multiple clients to share files, since clients can access files as if they were local files, with the exception that they must be accessed over a network. In this way, common files can be maintained in a central location, and accessed by many clients, which eliminates the need for multiple copies of files on multiple client systems. In addition, this improves data integrity, data security and reduces costly duplication of files. Major applications that benefit from the use of NAS to share large amounts of information include CAD/CAM (Computer Aided Design/Computer Aided Manufacturing), document management, imaging as well as other similar application serving environments.

Because data travels over the network, NAS is not always suitable for applications such as data warehouses and On-Line Transaction Processing (OLTP), since these applications need to sustain high I/O data rates with little, or no degradation in response times to the clients.

- You Can Write/Contribute & Win Some COOL Stuff
- Know Basically What is Storage Area Network
- If You want a High Paying Job what should be your Strategy.
- It has more than 90 interview questions listed in this single blog
Interview questions series 1
Interview questions series 2
Interview questions series 3
Interview questions series 4
Interview questions series 5
Interview questions series 6
Interview questions series 7
Interview questions series 8
Interview questions series 9
Interview questions series 10
- Know what happens in office routine of a Storage professional
- Know what sort of job roles are there in Storage area networking
- Know what they ask in a storage job interview
- Need guidance to revamp or improve your Resume
- It has one simple storage implementation Case study
- Basic questions a Software job hunter asks
- Answers for the questions like Job Opportunities in Storage
- Want to see details of Job requirement for Storage
- U like to take a Virtual tour of Cisco Production Data Center
- Every one talks about HA or High Availability - should'nt You
- Dont forget that Career in Any field requires dedication and hard work - U can do it Dude

Storage Basics: Storage Area Networks

2008-04-16T02:48:00.000-07:00

Many IT organizations today are scratching their heads debating whether the advantages of implementing a SAN solution justify the associated costs. Others are trying to get a handle on today's storage options and whether SAN is simply Network Attached Storage spelled backwards. In this article, I introduce the basic purpose and function of a SAN and examine its role in modern network environments. I also look at how SANs meet the network storage needs of today's organizations and answer the question, could a SAN be right for you.

Peel away the layers of even the most complex technologies and you are likely to find that they provide the most basic of functions. This is certainly true of storage area networks (SANs). Behind the acronyms and revolutionary headlines, lies a technology designed to provide a way of offering one of the oldest of network services, that of making access to data storage devices available to clients.

In very basic terms, a SAN can be anything from two servers on a network accessing a central pool of storage devices to several thousand servers accessing many millions of megabytes of storage. Conceptually, a SAN can be thought of as a separate network of storage devices physically removed from, but still connected to, the network. SANs evolved from the concept of taking storage devices, and therefore storage traffic, off the LAN and creating a separate back-end network designed specifically for data.

SANs represent the evolution of data storage technology to this point. Traditionally, on client server systems, data was stored on devices either inside or directly attached to the server. Next in the evolutionary scale came Network Attached Storage (NAS) which took the storage devices away from the server and connected them directly to the network. SANs take the principle one step further by allowing storage devices to exist on their own separate network and communicate directly with each other over very fast media. Users can gain access to these storage devices through server systems which are connected to both the LAN and the SAN.

This is in contrast to the use of a traditional LAN for providing a connection for server-storage, a strategy that limits overall network bandwidth. SANs address the bandwidth bottlenecks associated with LAN based server storage and the scalability limitations found with SCSI bus based implementations. SANs provide modular scalability, high-availability, increased fault tolerance and centralized storage management. These advantages have led to an increase in the popularity of SANs as they are quite simply better suited to address the data storage needs of today's data intensive network environments.

The advantages of SANs are numerous, but perhaps one of the best examples is that of the serverless backup (also commonly referred to as 3rd Party Copying). This system allows a disk storage device to copy data directly to a backup device across the high-speed links of the SAN without any intervention from a server. Data is kept on the SAN, which means the transfer does not pollute the LAN, and the server processing resources are still available to client systems.

SANs are most commonly implemented using a technology called Fibre channel (yes, that's fibre with an 're', not an 'er'). Fibre Channel is a set of communication standards developed by the American National Standards Institute (ANSI). These standards define a high-performance data communications technology that supports very fast data rates (over 2Gbps). Fibre channel can be used in a point-to-point configuration between two devices, in a 'ring' type model known as an arbitrated loop, and in a fabric model.

Devices on the SAN are normally connected together through a special kind of switch, called a Fibre Channel switch, which performs basically the same function as a switch on an Ethernet network, in that it acts as a connectivity point for the devices. Because Fibre channel is a switched technology, it is able to provide a dedicated path between the devices in the fabric so that they can utilize the entire bandwidth for the duration of the communication.

The storage devices are connected to Fibre Channel switch using either multimode or single mode fiber optic cable. Multimode for short distances (up to 2 kilometers), single mode for longer. In the storage devices themselves, special fiber channel interfaces provide the connectivity points. These interfaces can take the form of built in adapters, which are commonly found in storage subsystems designed for SANs, or can be interface cards much like a network card, which are installed into server systems.

So, the question that remains is this. Should you be moving away from your current storage strategy and towards a SAN? The answer is not a simple one. If you have the need to centralize or streamline your data storage then a SAN may be right for you. There is, of course, one barrier between you and storage heaven, and that's money. While SANs remain the domain of big business, the price tag's of SAN equipment is likely to remain at a level outside the reach of small or even medium sized businesses. As the prices fall, however, SANs will find their way into organizations of all sizes, including, if you want, yours.

Software Testing Interview Questions for Testing Jobs

2008-04-16T02:47:00.002-07:00

Below are some basic concepts you need to know about Software Testing.

1.What is Software Testing?
Software testing is the process of executing a software application or program to find defects,report them & get them resolved .This is to mainly remove more defects from the product & improve quality.

2.What is the difference between QA & QC , Quality Assurance & Quality Control ?

QA is focussed on removing defects in the first place
QC is focussed on finding more defects which are already in the developed product

QA is process oriented
QC is product oriented

QA tries to put in place lots of process improvements at the initial phases of development to make sure product quality is better & there are fewer bugs/defects.(Example : Code reviews,walkthroughs,inspections)

QC is at the later stages of development where QC team has a executable build to test & QC tests with the intent of finding more bugs

3.What is a defect or a bug ?

A bug or a defect is a deviation from what is expected in the functional specifications . These are problems or issues which decreases the quality of the product. A company which develops a product (Hardware or Software) wants to remove as many defects as possible (Improving the quality) before the product is released to the Customer/End User.

4.What is AUT or PUT ?
Application Under Test
Product Under Test

Software Testing Interview Questions : Top 10 Questions asked in many interviews

2008-04-16T02:47:00.001-07:00

Below 10 Questions are frequently asked in any Testing Job Interviews :
1. How did you Test your Project "Customer Records Management"(Example project)?

2. How is your Testing process ?

3.How is your Test cycle schedule & what are the components you have been testing ?

4. If you find a bug/defect what will you do ? How is your defect management process ?

5. How does the Testing Team Interact with Development team in your Company ? When & how do you communicate with Product Development or Engineering team with regards to your Testing issues ?

6. What is a Product defect/issue and what is a Test setup defect or Test issue ?

7. How many bugs you have filed till now & mention 3 challenging bugs you filed ? Mention 2 high priority or critical bugs you filed & how were they resolved ? How did you do the root cause analysis for them (RCA) ?

8.You file a bug & developer marks it as "Not a bug" or "User Error" or "Not reproducible" & closes the bug - what will you do ?

9. How do you make sure you are giving maximum information in your bug report ? Which bug management tool do you use ? what are the different fields in your bug tracking software ?

10. How is your Testing project's configuration managent ? Which Versioning system you use ?

Testing Interview Questions & Interview experience in Symphony (continued)

2008-04-16T02:45:00.000-07:00

1st round of Technical discussion went for more than 20-25 minutes I was able to answer satisfactorily though I could not answer some of the questions related to Quality Metrics, Traceability matrix, Testing Unix processes/daemons

I was asked to wait after the second round & I waited for another 20-25 minutes.

2nd Technical Round
This was a more rigorous round .3 guys together interviewed me in this round - where they asked me to explain each of my projects, tools I used , way I handled my testing effort & things I learned.

Questions were like :
1. Did you write Test plan , Test cases for this project ?

2.How did you create test data & what methods you followed for that ?

3.Explain 5 challenging test cases from ur project tell me how you execute them starting from preparing the test setup for them ?

4.Write test cases to test "Winamp MP3 player" Write test cases to test "Norton Antivirus" Write test cases to test "Network Management Software"?

5.How do you give estimates for your testing efforts. What factors you will list out in the estimation document ?

6. What are these SRS,Func Specs - Explain how you translate Specs to Use cases to Test cases?

7. Which OS does your Software support ? Suppose it is supported in Windows only then you have so many configurations like :
Windows 2000 Professional
Windows 20000 Server
Windows XP Home
Windows XP Pro
Windows XP Pro with Service Pack2
Windows 2003 Standard Edition Server
Windows 2003 Enterprise Edition Server
Windows Vista Ultimate

So above 8 OS if we consider on Intel & again on AMD processors we have nearly 16 configurations multiply this with Hardware Server differences like "Dell PowerEdge Servers", "Sun microsystems - Opteron V20z Servers" , "IBM eSeries Server" you have 16 X 3 = 48 configurations - support you join a new team where you have to test all these configurations for 100 test cases how will you manage. Do you have a process in your present team to solve such a complexity

8. Explain Entry Criteria & Exit Criteria in your Test plans & How your project Test plan guides your whole testing process ?

9. Explain in detail all the tasks you do in your whole test cycle ? how much time you need for different test cases & what are the kind of issues you might face regularly? How do resolve those issues ? Have you implemented any best practices to resolve these issues in future ?

10. What are the things you have in your Performance plan for this year & how are you improving your self in this present job in terms of Technical expertise & Product knowledge?

There were many many more interview questions which I may send later. This round was the lengthiest & went for nearly 30-40 minutes. Good answers were appreciated & many a times interviewer's answered few things which I could NOT answer. It was a very learning experience for me & refreshing one too.

Symphony Services Interview Questions on Software Testing Engineer Job description

2008-04-16T02:44:00.000-07:00

Symphony Services hires lots of Testing Engineer's frequently.One of the blog reader attended its interview last week & find below his QA job interview experience.

Rounds : 5
1. HR Interview
2. Technical Brief
3.Technical Detailed
4.Manager Discussion
5.HR Discussion including salary & joining date/notice period

HR Interview
This initial HR round was mainly to filter out NOT-So-Good candidates. They asked asked
1.Company details : Website,Contact No.s & References (May be for further background verification - not sure)
2.Organization structure & company employee strength
3.My experience details of all previous companies
4.My roles & responsibilities , Skillset/Expertise

This was about 10 to 15 minutes & the person wrote down many details in another sheet & took for records.

I had to wait another 20 minutes to go for next round ( I was glad to know they were interested to take me to next round - which I considered as the actual starting of the interview process)

1st Technical Round
The tech lead who took my interview was very serious & looked like tired of taking many interviews. Still i appreciate his patience of asking quality interview questions like
1.Explain the tasks you are responsible for in this Testing project

2.How do you manage growing features & how you keep track that testcases are also increasing to have proper coverage

3.Explain your test scenarios & what bugs you found in which scenarios

4.How were you involved in Integration testing & how were your testing efforts contributing interms of improving the quality of the product under test.

5.Explain some of the component areas you have worked till now in this company/project. Which one was most challenging & why?

6.What is regression testing? How is Regression testing done in your team ? Tell me some what is a regression bug & name 3 regression bugs you filed & what was their priority

7. When you file a bug what happens till it gets fixed? Explain all the phases & people involved in this bug detection till resolution process

8. Apart from Testing an application or Product what else you did in your whole experience ?

9. Do you know about Performance Testing can you explain how would you approach it if you had to start doing it even though you may not have much prior experience ?

10. What is End 2 End testing ? What are these FCS,RTM,GA,RC ?

Testing Interview Questions & Interview experience in Accenture

2008-04-16T02:42:00.000-07:00

Accenture is one of the biggest & best paying companies. It has lots of projects worth millions & even billions & best part is it hires lots of Software testing professionals.

Here is one of the interview experience of Accenture.
There will be nearly 4 to 8 rounds depending on the years of experience you have & level of designation you are applying for.

Do Not attend their interview without proper preparation. They take very challenging & aggressive interview & the whole hiring process is very streamlined . So sometimes they may take a month before giving you a Job Offer. Have patience & do your best in Interview.

Some of the questions asked in Accenture Software Testing Interview are :

1. Explain Traceability matrix & how is it used in your project? Who is responsible in your team to manage it & if you were assigned that task how will you be able to manage it?

2. How was the regression testing done in your project what was the contribution of the regression test effort for the whole quality improvement?

3. Write or explain 15 testcases you executed recently with detailed descriptions ,steps to reproduce & explain what results they gave when you executed on a recent build?

4. Mention 5 testcases or a test component area which gave lots of bugs & had lots of difficulties in testing it ?

5. How is the Release Engineering process in your team? When codefreeze happens when you get a QA build & what are the factors considered before you start testing this build?

6. What are the SLA's(Service Level Agreements) Testing team has with Development team ?

7. How is the sustaining or Customer escalations team interacting with testing team ? How do you transition your projects to Sustaining team once you move to new release or new version testing?

8. What is Cyclomatic complexity ? Did you ever use it in your testing efforts ?

9. What are some of the tasks that you are handling which are transitioned to you by your lead?(Mean to ask what tasks of a lead are you performing , if any) [Intention of the question is whether you will be able to rise above your limits & take bigger initiatives when required]

10. How will you manage a critical projects when
- Experienced Senior people are leaving
- There is limited time to test a lot of scenarios & configurations
- There are many hardware/infrastructure issues
- The knowledge transfer from development team is not enough
- The documentation is very minimal & the test plans are not very precise

What People are Searching for on this "Software Testing Jobs Blog" : This is very interesting

2008-04-16T02:41:00.000-07:00

Below are the words people searched in Google & found my blog as answers & came to this blog by clicking the results in google search listing. I guess many of them have found their answers on the different pages of this blog. This is very intersting list to read & understand how people search on the google. I promise to write more to answer their search questions.Keep reading this blog daily.

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Testing Interview Questions from Accenture Software Testing Engineer Interview

2008-04-16T02:40:00.000-07:00

First round was HR round : HR person who took my interview also asked few technical related questions apart from the usual HR general questions :

1. Explain your present role & responsibility.

2. Why are you looking for a job change ?

3. If given a chance will you lead a team & do you have any prior experience in that ?

4. What importance you think "Testing Engineer" & Testing Team plays ?

5. Were you interacting directly with the clients ? Were you required to interact with other
teams & teams spread across different geos ?

6. How were your experience in all the companies you worked previously ? What are the
achivements you can mention & are there any excellence recognition you've got so far ?

7. Present Salary , Expected Salary, Notice period - can the notice period be shortened - can I join immediately within a week if required?

8. What are my hobbies & interests ?

9. What about my family background & Do I have any difficulty in relocating ?

10.What value addition will I bring If I was offered the job ? How can I prove that I will be associated with this company for a considerably longer period of time ?

11.What are the processes our company followed ? am I familiar with CMM or Six sigma or any other maturity model ?

Basic questions asked in any Software Testing Interview

2008-04-16T02:39:00.000-07:00

1. What is Testing ?
Testing is finding out how well something works. But the proper definition is "Testing is the process of executing a set of instructions or steps to know how well a Software application or any product adheres to the product specifications"

Testing is the process of finding defects in a software application , reporting it & making sure the defects or bugs are fixed by the development. Once the development does the fixes for the reported defects Testing team is again responsible to verfiy the fixes & making sure the new fix has not broken any previously working functionality of the product.

2. What is a Defect or a Bug or a Product issue ?
Any deviation from the specifications mentioned in the product functional specification document is a [b]Defect[/b]. A defect or a bug is a mistake in the software application or AUT[Application Under Test] considering the details mentioned in the detailed specification document.

So if some feature or functionality of a Software application is varying from what it is supposed to be[with regard to its expectations mentioned in the Specification documents] it is considered a bug or a Defect. Some companies use the term CR: Change Request for a bug.

3. What will you do when you find a Defect in the product that you are Testing ?
Different companies follow different processes or methods in this case but generally when we find a bug or defect we report it following the bug logging process or Defect Reporting . But it is also the job of a Testing Engineer to make sure it is a real product bug & not any setup or testcase issue before filing a defect report [Bug Logging]

4. How do you log a bug & what software you use for this process ?
We use Bugzilla which is an opensource software for logging bug. While logging a bug we need to give detailed information about the whole steps i've done when i encountered this bug or defect.

When we hit a defect i mean while executing some testcase if we encounter a bug , we need to inform the developers & also concerned like Program manager,Development Lead,Test Lead etc. Bug reporting is a process of such communication. The main aim of a bug report is to let the developers know the details of the failure & to help them to find a resolution for the issue . So it is very important to give detailed information so that whoever is reading the bug report or trying to reproduce the bug can do so easily . The bug report is a document that explains the gap between the expected result and the actual result and detailing on how to reproduce the scenario.

5. Describe in detail what you should do after Finding the Bug?

Write the bug report just when you are sure that you have found a bug, not after the end of test or at the end of the day. It might be possible that you might miss out on many crucial points if you are delaying the write up for bug filing . Worse, you might miss the bug itself.
Put necessary time to diagnose the defect you are reporting. Think of the possible causes. You might land up uncovering more defects if there are any . Mention your discoveries in your bug report. The programmers will only be happy seeing that you have made their job easier. Take some time off before reading your bug report. You might feel like re-writing it.

6. What are the factors you consider while writing Defect Summary or bug synopsis ?

The summary of the bug report is the readers first glance with your bug report. The fate of your bug heavily depends on how well you compress yet describe the summary of your bug report. The rule is that every bug should have a one line summary some reporting softwares call it as Bug Synopsis. A good summary will not be more than 50 to 60 characters.

Fast Solution to Get a High Paying Job in the Best Technology Company

2008-04-10T02:57:00.000-07:00

Is there a fast solution to get a Good job?

Can I somehow get a very good salary job fast?

What should I do to get that dream job soon ?

These are some of the questions many people email me with & people search frequently online. I am trying to list solutions,answers for these questions.

1.Best Time Management : Get to know Which company pays highest & Which profile does it pay a very good salary for.

2.Learn Fast Retain most : If you already suit above profile then you are lucky if not then you need to learn lots of stuff fast & also should retain a lot. More than anything a company wanna hire an experienced expert & not some one very good in theory. So u need to work fast, work smart & then learn from others experience. Internet helps u a lot in this. An example is this blog which has lots of interview questions highlighting what topics to stress more.Also videos which explain & show the things. In future I will write about tech topics along with their practical configuration etc which are practical.

3.Have a good Support System : Who can get you inside information or can help you get some advantage like who can teach you Server administration in a crash course, who can let you know which company is hiring in your nearby place, who can help you know how you can setup your own scaled down storage lab etc etc . You basically need someone who is more than a good friend.

4.Stick to the goal & be very positive : Results will not happen in a day. So you need to have consistency in your efforts. If I say read all 100+ posts on this blog & you will get a job for sure - how many of this blog's readers will try that. I am sure not even 1 person can have the patience to read all 100+ posts on this blog. But to my amazement a guy from Japan has gone through all the posts on this blog & taken print out made it as a small reference book. He emailed me yesterday saying that he got a nice job since he used this blog as his support system. Yes for him this blog served the purpose of being more than a friend. I am glad someone made a very positive use of the amount of knowledge available on this blog.

VMware Virtual Infrastructure 3 ESX Server Virtual Center Server Interview Questions

2008-04-10T02:54:00.000-07:00

Vmware Technical Interview Questions. I was able to compile good list of 100 Vmware Interview Questions with Answers. Since Vmware is a hot technology & there are lots of job opportunities opening up for Vmware ESX administrator,Vmware Certified Professionals: lot of people are searching for "vmware interview questions" in Google.
I checked this keyword on Google & did'nt find any other website or blog giving info other than this blog "Storage Jobs Blog". Though there are lot of Vmware professionals they are too experienced & they feel this thing called "Interview Questions List" is not a big deal. They have such a cool years of experience & knowledgebase on Vmware that they are busy with their Virtualization project implementation & they DO not have time to attend any interviews. These guys in Vmware Virtualization domain are paid so well that they DO NOT have to worry about changing job or changing company.

Please find below 10 technical questions on Vmware ESX Server , Virtual Center & Virtual Infrastructure 3. More Questions with answers will be posted soon. But apart from this list if you want a single document of 100 Interview Questions with Answers - click on the Paypal Big button at the right side of this blog. This document containing 100 "Vmware technical Interview Questions & Answers" will never be published anywhere it is available for only people who are willing to pay $100. Yes the cost of this document is $100 . Along with this doc you will get several PDF files which detail many technical aspects of Vmware Virtualization which will be given FREE. Anyone who can clear & get a job in Vmware virtualization is going to get a pay of more than US $6000- $9000 Per month. So the price of $100 is less compared to the advantage U have by buying this. Email roger.smithson@gmail.com for more info.

Below are 10 Interview Questions with Answers on Installation and Upgrade of ESX 3.0.1 and Virtual Center 2.0.1

Installation and Upgrade of ESX 3.0.1 and Virtual Center 2.0.1

1.List the major components of Vmware Infrastructure ?
* The major components of VMware Infrastructure are:
ESX Server host .
Virtual Center Server.
Virtual Infrastructure (VI) Client .
Web browser.
License server.
Database.

2. What are the minimum H/W requirements to install VirtualCenter Server ?
* VirtualCenter Server hardware must meet the following requirements:
Processor : 2.0GHz or higher Intel or AMD x86 processor. Processor requirements can be larger if your database server is also run on the same hardware.

Memory : 2GB RAM minimum. RAM requirements can be larger if your database is run on the same hardware .
Disk storage :Nearly 1GB free disk space
Networking : 10/100 Ethernet adapter minimum (Gigabit recommended).
Scalability : A VirtualCenter Server configured with the hardware minimums can support 20 concurrent clients, 50 ESX Server hosts, and over 1000 virtual machines.

A dual processor VirtualCenter Server with 3GB RAM can scale to 50 concurrent client connections, 100 ESX Server hosts, and over 2000 virtual machines.

3. Which softwares are supported to install Virtual Center Server Software ?
* The VirtualCenter Server is supported as a service on the 32 bit versions of these operating systems :
The Virtual Center installer requires Internet Explorer 5.5 or higher in order to run.
o Windows 2000 Server SP4 with Update Rollup 1 (Update Rollup 1 can be downloaded from Windows XP Pro (at any SP level)
o Windows 2003 (all releases except 64 bit)

Virtual Center 2.0 installation is not supported on 64 bit operating systems.

4. Which Databases are supported to VirtualCenter ?
* Virtual Center supports the following database formats:
o Microsoft SQL Server 2000 (SP 4 only)
o Oracle 9iR2, 10gR1 (versions 10.1.0.3 and higher only), and 10gR2
o Microsoft MSDE (not supported for production environments)

5. What are the Hardware requirements for Virtual Infrastructure Client ?
* The Virtual Infrastructure Client hardware must meet the following requirements :
o Processor : 266MHz or higher Intel or AMD x86 processor (500MHz recommended).
o Memory . 256MB RAM minimum, 512MB recommended.
o Disk Storage . 150MB free disk space required for basic installation. You must have 55MB free on the destination drive for installation of the program .
o Networking . 10/100 Ethernet adapter (Gigabit recommended).

6. Which softwares are supported for Virtual Infrastructure Client ?
* The Virtual Infrastructure Client is designed for the 32 it versions of these operating systems:
o Windows 2000 Pro SP4
o Windows 2000 Server SP4
o Windows XP Pro (at any SP level)
o Windows 2003 (all releases except 64bit)

The Virtual Infrastructure Client requires the .NET framework 1.1 (included in installation if required).

7. What are the Requirements for VirtualCenter VI Web Access ?
* The VI Web Access client is designed for these browsers :
o Windows . Internet Explorer 6.0 or higher, Netscape Navigator 7.0, Mozilla 1.X, Firefox 1.0.7 and higher.
o Linux . Netscape Navigator 7.0 or later, Mozilla 1.x, Firefox 1.0.7 and higher.

8. What are the Minimum Hardware Requirements for ESX Server 3.x ?
* You need the following hardware and system resources to install and use ESX Server.
At least two processors:
o 1500 MHz Intel Xeon and later, or AMD Opteron (32bit mode) .
o 1500 MHz Intel Xeon and later, or AMD Opteron (32bit mode) for Virtual SMP.
o 1500 MHz Intel Viiv or AMD A64 x2 dualcore processors
1GB RAM minimum.
One or more Ethernet controllers. Supported controllers include:
* Broadcom NetXtreme 570x Gigabit controllers
* Intel PRO/100 adapters
For best performance and security, use separate Ethernet controllers for the service console and the virtual machines.
A SCSI adapter, Fibre Channel adapter, or internal RAID controller:
* Basic SCSI controllers are Adaptec Ultra160 and Ultra320, LSI Logic Fusion MPT, and most NCR/Symbios. SCSI controllers.
* RAID adapters supported are HP Smart Array, Dell Perc RAID (Adaptec RAID and LSI MegaRAID), and IBM (Adaptec) ServeRAID controllers.
* Fibre Channel adapters supported are Emulex and QLogic host bus adapters (HBAs).
A SCSI disk, Fibre Channel LUN, or RAID LUN with un partitioned space. In a minimum configuration, this disk or RAID is shared between the service console and the virtual machines.

9. Which Storage systems supports for installing and booting ESX Server ?
* ESX Server supports installing and booting from the following storage systems:
IDE/ATA disk drives Installing ESX Server on an IDE/ATA drive or IDE/ATA
RAID is supported. However, you should ensure that your specific drive controller is included in the supported hardware.
Storage of virtual machines is currently not supported on IDE/ATA drives or RAIDs. Virtual machines must be stored on VMFS partitions configured on a SCSI drive, a SCSI RAID, or a SAN.
SCSI disk drives . SCSI disk drives are supported for installing ESX Server. They can also store virtual machines on VMFS partitions.
Storage area networks (SANs) . SANs are supported for installing ESX Server. They can also store virtual machines on VMFS partitions.

10. Enhanced Performance Recommendations for ESX Server
* Some recommendations for enhanced performance:

RAM : Having sufficient RAM for all your virtual machines is important to
achieving good performance. ESX Server hosts require more RAM than typical
Servers : An ESX Server host must be equipped with sufficient RAM to run
concurrent virtual machines, plus run the service console.

Dedicated fast Ethernet adapters for virtual machines : Dedicated Gigabit Ethernet cards for virtual machines, such as Intel PRO/1000 adapters,iimprove throughput to virtual machines with high network traffic.

Disk location . For best performance, all data used by your virtual machines should be on physical disks allocated to virtual machines. These physical disks should be large enough to hold disk images to be used by all the virtual machines.

VMFS3 partitioning . For best performance, use VI Client or VI Web Access to set up your VMFS3 partitions rather than the ESX Server installer. Using VI Client or VI Web Access ensures that the starting sectors of partitions are 64K aligned, which improves storage performance.

Processors . Faster processors improve ESX Server performance. For certain workloads, larger caches improve ESX Server performance.

Hardware compatibility . To ensure the best possible I/O performance and workload management, VMware ESX Server provides its own drivers for supported devices. Be sure that the devices you plan to use in your server are supported.

Virtual Network Storage Architecture

2008-04-10T02:53:00.000-07:00

Benefits of virtualization
- Significantly reduce downtime
- Improved performance: load spreading, balancing, multi-path, heuristic shifting
- Improve delivery and quality of storage services
- Simplify definition of storage policies and procedures.
- Managed file systems and volume mangers increase the scalability, reliability, security.
- Provides storage location and implementation transparency.
- Enables dynamic operations, storage systems reconfiguration and data location to change transparently to host environment.

Virtual Storage Appliance
- VTL (Virtual Tape Library) server.
- CDR (Continuous Data Replication) Backup/Recovery Server
- iSCSI server for Disaster Recovery
- Cluster System

Functionality of virtual storage subsystem
- Enhance the service quality of storage device/data, easier maintain system expansion, simplifies and centralizes the management of storage system, cut down the storage budget cost.
- Efficiently and simplify the functionality of following:
a. Data Backup and Restore
b. Cluster storage structure; enhance the capability of fault tolerance, I/O balancing, failover and fail-back.
c. 256 Snapshot Point in Time Data Replication
d. Data integration, migration and consolidation, simplify the management of storage system.
e. Disaster recovery, to rapidly resume system operation.
f. Load Spreading, Balancing, Caching, Security.

Above article courtesy:tekram.com/news/news_detail.asp?id=6

Fibre Channel Network Architecture brief introduction

2008-04-10T02:52:00.000-07:00

FC Network protocol & architecture are other important topics any storage professional should be aware of.
Fibre Channel Protocol

Fibre Channel Overview
Fibre Channel is a networking standard that is designed to move data through specific devices at specific speeds. Initially, Fibre Channel was used primarily to attach servers to a storage device, such as a RAID array or a tape backup device. More recently, Fibre Channel has evolved as the architecture of choice for many storage area networks. Fibre Channel is ideally suited to this role because it is very reliable, very scalable, and very flexible. It's possible to add more storage without disrupting operations, use a number of backup schemes that don't load the main network, and manage very large data collections that span multiple disks.

Fibre Channel is a high speed (100 to 800 Mbps) medium used for data transfer and storage. Fibre Channel provides a logical bi-directional, point-to-point connection between a host and a device. It is essentially a serial data channel created over fiber optic cabling which makes it possible to transfer data at much greater distances than SCSI and ATA interfaces.

Fibre Channel is designed to work with either copper wires or with fiber. Although copper is used only for shorter distances, a variety of copper mediums can be used, including telephone wire or coaxial cable. If fiber optic cable is used, distances of about six miles can be achieved with minimal loss of speed. Another advantage of dedicated channel based communication is its ability to provide increased bandwidth than network based links.

Features and Benefits
Storage Area Networks are not new ideas in data storage, however they are increasing in popularity due to high demand by users who need to store large volumes of data. A SAN is a group of storage devices connected via a network of connections to host computer or server. The primary advantages of SANs are:
* Storage resource pooling/sharing
* LAN and server-free backup
* Centralized storage resource management
* Data sharing - Large number of users
* Performance - High Speed, Low Latency
* Distance (>10KM)

Architecture
Channels and networks are the two primary ways that data is transferred between devices. Fibre Channel uses channels and frames instead of packets to move data. Each frame is approximately 2KB in size. Of this amount, 1.5 percent is header information. Channels transfer data through switched or direct point-to-point connections and they work by creating a fixed connection between the source and destination devices until the transfer is complete.

Connections are made on Fibre Channel systems through "interconnection components" including switches, hubs, and bridges. The ability of Fibre Channel to use different interconnect devices makes it scalable depending on user needs. For small Fibre Channel networks, hubs and bridges may be used for connecting devices in a topology called Fiber Channel arbitrated Loop (FC- AL). As Fibre Channel networks get larger and network demands increase, switching may be implemented. A switched Fibre Channel network is called a fabric.

Fabric topology permits multiple paths between two ports on the Fabric. Loop topology, on the other hand, there can only be one active circuit at a time. Loop and Fabric topologies can be combined to provide both connectivity and performance. If a link in a point-to-point topology fails, communication between that pair of ports stops. Communication between other point-to-point connected Ports continues.

Fiber optics are excellent for transmitting data across a network because they are reliable. They do not have the same problems that are associated with copper cabling such as attenuation (loss of signal strength) and noise. It is also more secure than copper because crosstalk does not occur with Fiber Optic cables. Fibre Channel traffic can also be transmitted over other cable types such as copper, coaxial cables or Unshielded twisted pair (UTP) wires.

Class of Service - Fibre Channel technology makes use of classes of service to define communication between devices.

* Class 1 a dedicated channel between two connection devices. In this configuration, if a host and a device are connected, no other host can use that connection. The advantage of using service class 1 is speed and reliability.
* Class 2 is known as a "connectionless" service. It a frame-switched link that guarantees delivery of packets from device to device and packet receipt acknowledgments.
* Class 3 is called unacknowledged connectionless service and is good for broadcasts. This configuration allows multiple transmissions to be sent across the Fibre Channel fabric to multiple devices.
* Class 4 is called "intermix", which creates a dedicated connection but it also allows class 2 traffic to access the link. This method is very efficient and it allows for greater bandwidth because more than one connection can access the system at any time.

For more info u can read on ::www.lecroy.com/tm/Solutions/Protocol/fibrechannel.asp?menuid=

Storage architecture SAN architecture FC Network architecture

2008-04-10T02:45:00.001-07:00

One of the Top question asked either in a Storage job profile interview or while attending a Client meeting is "Explain your system architecture". Based on whats their interest they may be interested to know about your
- Storage architecture
- SAN architecture
- FC Network architectiure

So this post has few images & some good links to help you learn more on these Very important topics

Storage architecture: Storage architecture design should follow a structured approach to ensure that the correct solution is adopted by the organization. The three basic types of storage architectures that are discussed in this blueprint(microsoft.com/technet/solutionaccelerators/wssra/raguide/ArchitectureBlueprints/rbabst_2.mspx) are:
- Distributed Storage
- Hybrid Storage
- Centralized Storage
Each of these storage architecture types defines a storage pattern that can be used as a starting point for providing guidance on how the storage should integrate with the business needs of an organization. If business needs are not communicated when enterprise architecture issues are being considered, it is easy for new projects to focus only on their own requirements and miss the wider picture that an architecture encompasses.

A structured design process for a complete enterprise storage solution consists of:
•Determining the storage requirements.
•Choosing the storage technologies.
•Defining fault tolerance technologies.
•Defining backup and recovery technologies.

Hybrid Storage Example

Centralized Storage Example

SAN Architecture example

Please read forthcoming posts for more photos & details about FC & Network architecture

Veritas Interview Questions with answers : Veritas Cluster Server

2008-04-10T02:44:00.001-07:00

1. How do check the status of VERITAS Cluster Server aka VCS ?
Ans: hastatus –sum

2. Which is the main config file for VCS and where it is located?
Ans: main.cf is the main configuration file for VCS and it is located in /etc/VRTSvcs/conf/config.

3. Which command you will use to check the syntax of the main.cf ?
Ans: hacf -verify /etc/VRTSvcs/conf/config

4. How will you check the status of individual resources of VCS cluster?
Ans: hares –state

5. What is the service group in VCS ?
Ans: Service group is made up of resources and their links which you normally requires to maintain the HA of application.

6. What is the use of halink command ?
Ans: halink is used to link the dependencies of the resources

7. What is the difference between switchover and failover ?
Ans: Switchover is an manual task where as failover is automatic. You can switchover service group from online cluster node to offline cluster node in case of power outage, hardware failure, schedule shutdown and reboot. But the failover will failover the service group to the other node when VCS heartbeat link down, damaged, broken because of some disaster or system hung.

8. What is the use of hagrp command ?
Ans: hagrp is used for doing administrative actions on service groups like online, offline, switch etc.

9. How to switchover the service group in VCS ?
Ans: hagrp –switch -to

10. How to online the service groups in VCS ?
Ans: hagrp –online -sys

I thank all those who are contributing articles , interview questions, interview experiences, any other useful bit of information.

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2008-04-10T02:37:00.000-07:00

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Is there any shortcut for me to get High Salary Job

2008-04-10T02:35:00.000-07:00

This is the most frequently asked question. Everyone wants to get a very high paying job. But people have very little time & efforts if I ask them to slog to achieve this. So to answer the question are there any shortcuts. Yes there are but it again requires you to put some more time & effort.

Without time & effort the only short cut I practically see is buying the job OR winning the job using heavy power influence.

Since most can not afford it let me try giving some guidelines to help achieve a better Career progress.

There are high demand job openings in both Storage Technology as well as Virtualization (Server Consolidation)
Companies like EMC2,Network Appliance,IBM,HP,Vmware,Accenture,Cisco,Intel,AMD almost all the giants we can remember everyone is getting heavily in these technologies. All of these companies are hiring & they are hiring not few but hunderds of Professionals.

This Blog has lots of info to help in this regard

1. Start with an area of your interest (Example : Testing domain or System Administration or Storage administration or Virtualization implementation etc)
2. Start knowing about what are the sub components in this area
3. See if you can get some course/training for the same - crash course do help,but more than that how many hours,years you put to gain practical experience
4. Start preparing your resume ( This helps you have a clear road map - many feel this is the hardest part to start but it helps if you build a brief resume & start developing it as you progress)
5. Parallely increase your knowledge base on specific key areas of your selective domain
6. Build contacts with people who can help you increase your exposure & experience (may be an experienced person can make the whole learning easier for you)
7. Get involved in projects,open source initiatives & contribute as much as you can (THIS IS THE ONE MOST CRUCIAL STEP)
8. Start building your Resume : Put Projects, Your Efforts, Your tasks, Role, Responsibilties
9. Be able to present in a mock presentation what you've learnt so far
10.Develop your ability to expand & work on extreme challenges - for this your learning & working experience helps a lot
11. Keep reading this blog ( As you can learn a lot of new things quite fast & quite easily)
12.Start preparing for mock interviews , ask a friend to take mock interviews & know where you stand
13.Start preparing for real interviews, Increase the effectiveness of your resume & make sure you are perfect in everything you are mentioning in your resume
14.Start applying to job portals. (I will write a post soon about how you can leverage this for better success)
15.Never loose heart no matter how long this process takes or how many interviews go without results- You can definitely get JOB :)

Array-based Flash Memory Could Enable 1TB Memory Chips

2008-04-10T02:33:00.000-07:00

The alphabet soup of different flash memory technologies is already a little bewildering, but it looks like the latest entrant could end up being the most promising of all, with single chip storage capacities of 1TB expected within ten years. Called array-based memory, the tech has been under development at a company called Nanochip, Inc. for nearly 12 years, and it looks like the first working samples will go out next year. Although those first prototypes will have storage roughly equivalent to NAND flash at tens of gigs per circuit, the plan is to rapidly scale up to 100s of gigs and finally to 1TB on a single chip. Because the chips can be manufactured using conventional fabs and aren’t subject to the same manufacturing constraints as traditional flash, they may also end up being far cheaper per gigabyte. The company is being funded by a number of prominent tech giants, including Intel, and says the tech can be used to improve everything from USB keys to SSDs to enterprise-grade servers — wait, bigger, cheaper, and potentially better? Yeah, sign us up.

New Flash Drives From Super Talent Are Super Tiny

2008-04-10T01:53:00.000-07:00

I’m a big fan of Super Talent’s USB drives. They’re tiny, weightless, high capacity, tiny, high quality, cheap, and tiny. The new versions are more of all that stuff, and one of them is billing itself as “the world’s smallest” 8 gig USB flash drive, weighing less than a nickel and measuring 31.3mm x 12.4mm x 3.4mm. There are three different versions; all of them are packin’ 8 gigabytes inside, but one has a swiveling cover, one has a retracting cover, and one (the tiny one) is completely naked. They can survive shocks and being submerged in water, come with a lifetime warranty, and only cost $35 each. The cheaper 4 gig versions are available now, here, but I’d hold out for the 8 gig version if I was you.

Storage area network connectivity overview

2008-04-10T01:31:00.000-07:00

A storage area network (SAN) organizes a broad assortment of storage devices into a single storage resource that can then be provisioned, allocated and managed for the entire enterprise. Although issues like storage capacity, performance and management often receive the most attention, the connectivity between each SAN device plays a critical role in successful SAN deployment. Each switch and storage system on the SAN must be interconnected -- usually through optical fiber or copper cabling -- and the physical interconnections must support bandwidth levels that can adequately handle the peak data activities that occur. This overview details the role of Fibre Channel, Ethernet and iSCSI connectivity on a SAN.

Fibre Channel

Fibre Channel is the quintessential SAN interconnect and virtually every storage switch and storage platform provides Fibre Channel ports. Multiple Fibre Channel ports support simultaneous data streams, but individual ports can often be aggregated into groups for even higher effective bandwidth. As an example, the research guide notes that the InServ E800 Storage Server from 3PAR Data Inc. supports up to 128 Fibre Channel ports, while the TagmaStore AMS1000 from Hitachi Data Systems Inc. (HDS) provides up to eight Fibre Channel ports. Servers and other devices can also be fitted with Fibre Channel host channel adapters to enable an Fibre Channel interface.

As a serial interface, Fibre Channel bandwidth is denoted in Gbps. Early Fibre Channel implementations ran at 1 Gbps per port before doubling to 2 Gbps and then 4 Gbps. Another transition to 8 Gbps is beginning, but mainstream adoption is not expected until mid or late 2009. Also, 10 Gbps is used in interswitch links to connect Fibre Channel switches to each other. Fibre Channel operates with numerous protocols, most notably SAS and IP.

Fibre Channel can use several types of physical media. Twisted pair cable is used to cover relatively short distances at low speeds between Fibre Channel devices. Coaxial cables generally offer better shielding against signal interference and can run across somewhat longer distances. Optical fiber is routinely used to carry the fastest signals across distances up to 10 km.

Ethernet

While Ethernet connectivity is generally used on the greater local area network (LAN), its use in the storage area network has been limited by its relatively slow bandwidth. Traditional Ethernet ports support 10/100 Mbps -- far slower than Fibre Channel. This had limited Ethernet in the SAN to basic management tasks. For example, a storage device or switch might include a single Ethernet port that connects the device to the LAN where an administrator can manage the device across it. Ethernet typically uses two protocols; Transmission Control Protocol (TCP), which handles the organization of data into packets, and Internet Protocol (IP), which handles the way those data packets are addressed. In fact, the terms "Ethernet" and "TCP/IP" are often used interchangeably.

Ethernet bandwidth is increasing today, and 10 Gigabit Ethernet (10 GigE) is widely available for data centers, which boosts performance on the LAN and will eventually make Ethernet use more practical for carrying data on the SAN. One Gigabit Ethernet is now common on many servers and switches, and the eventual emergence of 10 GigE promises to put Ethernet on par with 10 Gbit Fibre Channel.

Traditional Ethernet LAN deployments used coaxial cables, but twisted-pair cabling (e.g., Category 5 or Category 6 Ethernet cables) is the most common LAN cabling. Ten GigE often relies on optical fiber with transmission distances up to 40 km, which makes the technology far more expensive and limits its use to network backbones. As copper cabling becomes available for 10 GigE, the technology should see far more use within data centers and storage area networks.

ISCSI and FCIP

Fibre Channel SANs have long been challenged by deployment expense and management complexity -- often keeping SANs out of reach of smaller IT organizations. The emergence of iSCSI eases these challenges by encapsulating SCSI commands into IP packets for transmission over an Ethernet connection, rather than a Fibre Channel connection. This approach eliminates Fibre Channel in favor of Ethernet, which allows iSCSI to transfer data over LANs, WANs or the Internet and supports storage management over long distances.

In actual practice, a user or application will cause the operating system to generate corresponding SCSI storage commands. Those SCSI commands and data are then encapsulated and IP headers are added to make packets. The packets can then be sent over an ordinary Ethernet connection. The remote end of the iSCSI connection disassembles the encapsulated content and passes the SCSI commands to the SCSI controller and storage device. This also works in reverse, so any data or responses can be sent back to the user or application across the Ethernet connection.

Although it is easier to manage than Fibre Channel, iSCSI still has two disadvantages for storage. At 1 GigE, it does not perform as fast as Fibre Channel. And Ethernet will drop packets during network congestion. These problems may be alleviated soon, thanks to the emergence of 10 GigE and Data Center Ethernet, a standard in development with the goal of providing Ethernet with quality of service levels, efficient multipathing and lower latencies while preventing dropped packets. Another alternative is FCIP. FCIP translates Fibre Channel commands and data into IP packets, which can be exchanged between distant Fibre Channel SANs. It's important to note that FCIP only works to connect Fibre Channel SANs, but iSCSI can run on any Ethernet network.

Storage vendors are working on an Fibre Channel over Ethernet (FCoE) standard to enable SAN and LAN convergence. FCoE would reduce cabling by using converged network adapters in place of Fibre Channel HBAs and NICs. FCoE adoption depends on the availability of Data Center Ethernet and is not expected to be widely adopted before late 2009. Unlike iSCSI, FCoE is not routable and is subject to the distance limitations of Fibre Channel.

History of Enterprise Disk to Disk Backup

2008-04-09T23:18:00.000-07:00

In the early days of the 20th century it was not clear that the car would eventually replace the horse (and walking) as the most popular method of personal travel. Horses were cheaper, more familiar and more reliable than the early generation of petrol driven cars.

At the turn of the second millenium the tape backup market had reached a seemingly unassailable position. 3 out of the top 10 fastest growing profitable US storage companies in the first half of 2001 were tape companies:- ADIC (40% revenue growth), Overland (59% revenue growth) and Qualstar (40% revenue growth).

But the widespread corporate adoption of the internet which led to the dotcom bubble was also laying the connection paths for offsite backup and replication technologies which would soon cure the compulsive obsession of manually removing storage media offsite.

In 2006 the tape market saw its steepest ever decline in suppliers with mergers and acquisitions shrinking the supplier base. The death rattle of the tape backup market has been heard, although it may survive as a static niche market for a few more years.

This timeline plots the main markers for the decline of tape and the storage market switch to D2d.

1987 - the world's first NAS company Auspex Systems is founded. Their first servers were listed in our SPARC Product Directory in 1992. But it took the industry many years to realise that these products were a new type of storage server rather than platforms for databases and web servers.

1994 - STORAGEsearch.com's publisher publishes the first directory of fibre-channel adapters. That was the start of the network storage market which would later be called SANs. The market was hotly contested - and in 1996/97 there were far more oems making FC adapters than there are today. Many of them advertised in our online directory.

1997 - STORAGEsearch.com's publisher creates an online directory of RAID systems.

March 2000 - STORAGEsearch.com created a dedicated web page for online backup and storage. By this time the internet infrastructure, beefed up to host corporate websites for the dotcom economy was sufficiently well established to make internet backup technically viable. Before this era - this type of offsite online backup was restricted to big corporations with leased data lines using proprietary technology.

2000 - FalconStor Software is founded. The company would later become an important enabler for white box storage oems entering the virtual tape market.

August 2000 - An article called - the Return of Removable Hard Disk Drive Architecture - summarised the state of the art in SMB disk backup with a comparison of removable storage devices from leading vendors.

December 2000 - NAS climbs to equal place with SAN to reach #5 in popularity with STORAGEsearch.com's readers.

March 2001 - STORAGEsearch.com created a dedicated web page for iSCSI

September 3, 2001 - STORAGEsearch.com ran its first banner ad for a D2d product for Nexsan Technologies (see below).

November 2001 - in an article called - the Next Decade in Storage - STORAGEsearch.com precisely foretold the reasons why D2d would eventually replace tape backup.

March 2002 - STORAGEsearch.com created a dedicated web page for D2d

May 2002 - ads on STORAGEsearch.com's main D2d page were split 50:50 between new D2d systems and tape libraries as you can see on the archived page.

December 2002 - in STORAGEsearch.com's year end review - SATA was named Product Category of the Year - based on reader pageviews. SATA hard drives provided a step change in capacity and system cost which later helped to accelerate the D2d market.

February 2003 - the first recorded occurrence of the term VTL (virtual tape library) appears in a joint news story by MTI Technology and Quantum.

April 2003 - STORAGEsearch.com reported on May 5, 2003 that reader pageviews for disk to disk backup in April 2003 exceeded pageviews for tape backup for the first time. "We're now at a watershed where users no longer have to choose tape just because their forebears did" - said editor Zsolt Kerekes at the time.

October 2003 - StoneFly Networks and CommVaultSystems launched a bundled D2D backup IP SAN system that starts at $33,995 for a 1TB solution.

November 2003 - commenting on the launch of its new ATAbaby disk array Nexsan's Senior Executive Vice President Diamond Lauffin said "The new ATAbaby Twins is another nail in the coffin of tape-based backup. No tape loader or library can deliver the same level of data protection and availability at anywhere close to this price."

January 2004 - COPAN Systems summarised the current state of the tape - verses D2d market. "Unfortunately, even with the advent of the new SATA disk systems at $10/GB, disk is still three to five times the cost of automated tape libraries making long term data management prohibitive. In addition, many enterprises are concerned with the reliability of SATA technologies."

August 2004 - Peripheral Concepts published the results of their market research into backup practises and plans in over 1,000 major IT sites. The report said:- "The population using disk in backup has grown to 62%, and is forecast to reach 76% penetration by 2005."

December 2004 - Engenio published an article called - Disk to Disk Backup versus Tape - War or Truce?

Commenting on this STORAGEsearch.com said "Will disk to disk backup make tape backup obsolete? That's a question that's been debated hotly here on STORAGEsearch for many years. At the extreme polarized ends of the argument are tape media makers like Sony, who in an article here made a case for the long term survival of tape, and at the other end of the argument are disk to disk supporters like STORAGEsearch whose editorial view (March 2004) has been that tape doesn't have a viable role the midsize market any more.

March 2005 - Quantum became the first major storage vendor to include data compression within a D2d product when it added its Optyon hardware based data compression technology to the DX-Series disk-based backup systems enabling 2T / hour backup performance. In addition to the cost savings compared to uncompressed solutions - an additional benefit is increased storage reliability for customers. Because they only need half as many disks in their disk backup population.

Overland claimed to be the #1 company in disk to disk backup, saying it had shipped more disk-based backup appliances than any other vendor:- more than 1,000 of its own REOs. I was sceptical about this leadership claim - but no one contested it at the time.

October 2005 - MaXXan Systems published an article called - Virtual Tape: Can You Afford to Ignore It?

Commenting on this STORAGEsearch.com said "Some of the growing sophistication in the market can be seen by the way that the marketing terminology has morphed from the early D2d (let's kill tape backup) to the current VTL (Virtual Tape Library - let's just see if they notice that it's more reliable and works faster - and don't tell them that there isn't a tape in the box) type of approaches."

May 2006 - in a white paper called "Total Data Protection" - Farid Neema, President of Peripheral Concepts wrote - "For the first time ever, more than one half of the surveyed managers consider the possibility of a tapeless IT operation in the long run. This aspiration for "getting rid" of tapes is even more pronounced in very large IT operations. In 2006, there will be more data backed up on disk than on tape, and disk should gain 4% share every year for the next three years."

August 2006 - D2d became the 4th most popular subject viewed by STORAGEsearch.com's readers (up from #15 in July). I commented - "Recent months have seen a spate of mergers and revenue attrition in the tape backup market - and the sharp increase in D2d content may signal that users no longer give credence to all the brave bullish talk they've been hearing from tape backup companies.

September 2006 - D2d became the 2nd most popular subject viewed by STORAGEsearch.com's readers.

October 2006 - D2d became the #1 most popular subject viewed by STORAGEsearch.com's readers. ...later:- and it remained #1 for the next 8 months too - upto and including May 2007.

Also in October 2006 - Network Appliance added data compression to its Virtual Tape Libraries.

December 2006 - D2D was named STORAGEsearch.com's Product Category of the Year 2006. In Q406 there was a surge of interest in D2D - which accounted for more reader pageviews than the next two subjects added together, despite annual pageview growth over 50% in those subjects too. "These results predict a stunning growth year for the disk to disk backup industry in 2007" said Zsolt Kerekes, editor STORAGEsearch.com.

January 2007 - Hitachi announced the industry's first terabyte hard drive priced at about 40 cents per gigabyte.

March 2007 - Enterprise Strategy Group quoted from their VTL Adoption and Market Trends Report that "85% of VTL users have already eliminated tape from their daily backup schedules."

April 2007 - STORAGEsearch.com reported that tape backup related searches had dropped out of the top 20 subjects viewed by readers in the preceding month.

June 2007 - Idealstor announced it had certified Hitachi's new terabyte hard disks for use with its Teralyte removable disk backup system.

November 2007 - NetApp's CEO Dave Hitz said in his blog this month "...I'm surprised how important creating real tapes from the VTL has remained. Despite all the hoopla about disk-to-disk backups, 80% of VTL customers still rely on tape for some part of their process."

December 2007 - Disk to Disk Backup is named STORAGEsearch.com's Product Category of the Year 2007 - for the 2nd year in a row.

Infiniband FAQs

2008-04-09T23:14:00.000-07:00

What is InfiniBand Architecture?
InfiniBand Architecture is an industry standard, channel-based, switched fabric, interconnect architecture for servers. InfiniBand architecture changes the way servers are built, deployed, and managed.

Why is InfiniBand Architecture important?
As processor speeds increase with Moore's Law and the Internet drives the demand for constantly available data, the biggest gate to improved data center performance is the I/O subsystem. InfiniBand Architecture provides a blueprint for significantly improved solution performance and increased availability to meet the needs of the Internet. InfiniBand Architecture is designed to fulfill the need for greater data center reliability, availability and scalability, as well as greater design density for InfiniBand architecture enabled servers.

What performance range is offered by the InfiniBand Architecture specifications?
InfiniBand Architecture offers three levels of link performance - 2.5 Gbits, 10 Gbits, and 30 Gbits/sec. InfiniBand Architecture also enables low latency communication within the fabric enabling higher aggregate throughput than traditional standards-based protocols. This uniquely positions InfiniBand Architecture as the I/O interconnect for data centers.

What will it take to integrate InfiniBand Architecture into a data center?
InfiniBand Architecture is expected to be implemented with existing data center implementations through connectivity into the InfiniBand fabric. Initial server implementations are expected to include InfiniBand Host Channel Adapters deployed on PCI adapter cards. As the technology evolves, native InfiniBand implementations are expected with a broad base of interoperable products from member companies. IT managers should talk to their suppliers about migration strategies to InfiniBand Architecture enabled solutions.

What is the expected demand for InfiniBand Architecture enabled solutions?
InfiniBand Architecture solutions create new opportunities for product development. According to IDC, initial InfiniBand architecture enabled servers are expected to ship in the first half of 2002 with 50% of total servers enabled with InfiniBand architecture by 2005.

What specific benefits do IT managers anticipate with InfiniBand fabric rollout?
IBTA IT program members have identified many areas of interest in InfiniBand fabric deployment including increased I/O performance for leading applications including database clusters, enhanced server density, and multi-vendor system interoperability.

How will InfiniBand fabrics be managed?
The InfiniBand Architecture specifications have standardized InfiniBand management infrastructure. InfiniBand fabrics will be managed via InfiniBand consoles and InfiniBand fabric management is expected to snap into existing enterprise management solutions.

How big is the InfiniBand Architecture development effort?
The InfiniBand Trade Association has grown from 7 companies to more than 190 since its launch in August, 1999. Membership is open to any company, department of government or academic institution interested in the development of InfiniBand architecture. To see a list of current trade association members please visit the roster.

When are products based on the InfiniBand Architecture Specification expected in the marketplace?
Initial InfiniBand fabric implementations are expected to appear in 2002. As with many new data center technologies, customers are expected to test InfiniBand architecture enabled solutions through pilot programs prior to mass rollout of the technology. To read about how some data centers are planning on using InfiniBand architecture visit www.infinibandta.org/itinfo/it.

Over sixty member companies have already announced plans for products based on InfiniBand Architecture. To see a list of member company InfiniBand architecture-related announcements visit www.infinibandta.org/newsroom/articles.

How does InfiniBand Architecture relate to 3rd Generation I/O technology (3GIO)?
The technologies are complimentary. InfiniBand Architecture was designed from the ground up to address the specific needs of data centers. In the server market, 3GIO is expected to be an inside the box interconnect, or local I/O.

What is the relationship between InfiniBand and Fibre Channel or Gigabit Ethernet?
InfiniBand Architecture is complementary to Fibre Channel and Gigabit Ethernet. InfiniBand architecture is uniquely positioned to become the I/O interconnect of choice for data center implementations. Networks such as Ethernet and Fibre Channel are expected to connect into the edge of the InfiniBand fabric and benefit from better access to InfiniBand architecture enabled compute resources. This will enable IT managers to better balance I/O and processing resources within an InfiniBand fabric.

How does InfiniBand Architecture relate to Rapid I/O?
Rapid I/O is one of many industry I/O technologies focused at embedded applications. Although it is possible to use InfiniBand Architecture in embedded designs, we believe the technologies have different focuses.

What type of cabling will the new I/O architecture support?
In addition to a board form factor connection, it supports both copper (up to 10 meters or longer) and fiber-optic cabling (up to 10km).

How many nodes will InfiniBand Architecture support?
InfiniBand Architecture is capable of supporting tens of thousands of nodes in a single subnet.

NAS, DAS or SAN? - Choosing the Right Storage Technology for Your Organization

2008-04-09T23:13:00.000-07:00

While one type of storage media is usually sufficient for smaller companies, large enterprises will often have a mixed storage environment, implementing different mediums for specific departments, workgroups and remote offices. In this paper, we will provide an overview of DAS, NAS and SAN to help you determine which solution, or combination of solutions, will best help you achieve your business goals.

DAS: Ideal for Local Data Sharing Requirements

Direct-attached storage, or DAS, is the most basic level of storage, in which storage devices are part of the host computer, as with drives, or directly connected to a single server, as with RAID arrays or tape libraries. Network workstations must therefore access the server in order to connect to the storage device. This is in contrast to networked storage such as NAS and SAN, which are connected to workstations and servers over a network. As the first widely popular storage model, DAS products still comprise a large majority of the installed base of storage systems in today's IT infrastructures.

3U 12 bay Infiniband storage
from Norco Technologies

Although the implementation of networked storage is growing at a faster rate than that of direct-attached storage, it is still a viable option by virtue of being simple to deploy and having a lower initial cost when compared to networked storage. When considering DAS, it is important to know what your data availability requirements are. In order for clients on the network to access the storage device in the DAS model, they must be able to access the server it is connected to. If the server is down or experiencing problems, it will have a direct impact on users' ability to store and access data. In addition to storing and retrieving files, the server also bears the load of processing applications such as e-mail and databases. Network bottlenecks and slowdowns in data availability may occur as server bandwidth is consumed by applications, especially if there is a lot of data being shared from workstation to workstation.

DAS is ideal for localized file sharing in environments with a single server or a few servers - for example, small businesses or departments and workgroups that do not need to share information over long distances or across an enterprise. Small companies traditionally utilize DAS for file serving and e-mail, while larger enterprises may leverage DAS in a mixed storage environment that likely includes NAS and SAN. DAS also offers ease of management and administration in this scenario, since it can be managed using the network operating system of the attached server. However, management complexity can escalate quickly with the addition of new servers, since storage for each server must be administered separately.

From an economical perspective, the initial investment in direct-attached storage is cheaper. This is a great benefit for IT managers faced with shrinking budgets, who can quickly add storage capacity without the planning, expense, and greater complexity involved with networked storage. DAS can also serve as an interim solution for those planning to migrate to networked storage in the future. For organizations that anticipate rapid data growth, it is important to keep in mind that DAS is limited in its scalability. From both a cost efficiency and administration perspective, networked storage models are much more suited to high scalability requirements.

Organizations that do eventually transition to networked storage can protect their investment in legacy DAS. One option is to place it on the network via bridge devices, which allows current storage resources to be used in a networked infrastructure without incurring the immediate costs of networked storage. Once the transition is made, DAS can still be used locally to store less critical data.

Serial Attached SCSI Chassis 1U to 5U
from Terabytes Server Storage Tech

NAS: File-Level Data Sharing Across the Enterprise

Networked storage was developed to address the challenges inherent in a server- based infrastructure such as direct-attached storage. Network-attached storage, or NAS, is a special purpose device, comprised of both hard disks and management software, which is 100% dedicated to serving files over a network. As discussed earlier, a server has the dual functions of file sharing and application serving in the DAS model, potentially causing network slowdowns. NAS relieves the server of storage and file serving responsibilities, and provides a lot more flexibility in data access by virtue of being independent.

NAS is an ideal choice for organizations looking for a simple and cost-effective way to achieve fast data access for multiple clients at the file level. Implementers of NAS benefit from performance and productivity gains. First popularized as an entry-level or midrange solution, NAS still has its largest install base in the small to medium sized business sector. Yet the hallmarks of NAS - simplicity and value - are equally applicable for the enterprise market. Smaller companies find NAS to be a plug and play solution that is easy to install, deploy and manage, with or without IT staff at hand. Thanks to advances in disk drive technology, they also benefit from a lower cost of entry.

In recent years, NAS has developed more sophisticated functionality, leading to its growing adoption in enterprise departments and workgroups. It is not uncommon for NAS to go head to head with storage area networks in the purchasing decision, or become part of a NAS/SAN convergence scheme. High reliability features such as RAID and hot swappable drives and components are standard even in lower end NAS systems, while midrange offerings provide enterprise data protection features such as replication and mirroring for business continuance. NAS also makes sense for enterprises looking to consolidate their direct-attached storage resources for better utilization. Since resources cannot be shared beyond a single server in DAS, systems may be using as little as half of their full capacity. With NAS, the utilization rate is high since storage is shared across multiple servers.

The perception of value in enterprise IT infrastructures has also shifted over the years. A business and ROI case must be made to justify technology investments. Considering the downsizing of IT budgets in recent years, this is no easy task. NAS is an attractive investment that provides tremendous value, considering that the main alternatives are adding new servers, which is an expensive proposition, or expanding the capacity of existing servers, a long and arduous process that is usually more trouble than it's worth. NAS systems can provide many terabytes of storage in high density form factors, making efficient use of data center space. As the volume of digital information continues to grow, organizations with high scalability requirements will find it much more cost-effective to expand upon NAS than DAS. Multiple NAS systems can also be centrally managed, conserving time and resources.

Another important consideration for a medium sized business or large enterprise is heterogeneous data sharing. With DAS, each server is running its own operating platform, so there is no common storage in an environment that may include a mix of Windows, Mac and Linux workstations. NAS systems can integrate into any environment and serve files across all operating platforms. On the network, a NAS system appears like a native file server to each of its different clients. That means that files are saved on the NAS system, as well as retrieved from the NAS system, in their native file formats. NAS is also based on industry standard network protocols such as TCP/IP, FC and CIFS.

Axstor, based in Coventry in the UK, provides
world class high-performance iSCSI storage
solutions at a cost-effective price point.

SANs: High Availability for Block-Level Data Transfer

A storage area network, or SAN, is a dedicated, high performance storage network that transfers data between servers and storage devices, separate from the local area network. With their high degree of sophistication, management complexity and cost, SANs are traditionally implemented for mission-critical applications in the enterprise space. In a SAN infrastructure, storage devices such as NAS, DAS, RAID arrays or tape libraries are connected to servers using Fibre Channel. Fibre Channel is a highly reliable, gigabit interconnect technology that enables simultaneous communication among workstations, mainframes, servers, data storage systems and other peripherals. Without the distance and bandwidth limitations of SCSI, Fibre Channel is ideal for moving large volumes of data across long distances quickly and reliably.

In contrast to DAS or NAS, which is optimized for data sharing at the file level, the strength of SANs lies in its ability to move large blocks of data. This is especially important for bandwidth-intensive applications such as database, imaging and transaction processing. The distributed architecture of a SAN also enables it to offer higher levels of performance and availability than any other storage medium today. By dynamically balancing loads across the network, SANs provide fast data transfer while reducing I/O latency and server workload. The benefit is that large numbers of users can simultaneously access data without creating bottlenecks on the local area network and servers.

SANs are the best way to ensure predictable performance and 24x7 data availability and reliability. The importance of this is obvious for companies that conduct business on the web and require high volume transaction processing. Another example would be contractors that are bound to service-level agreements (SLAs) and must maintain certain performance levels when delivering IT services. SANs have built in a wide variety of failover and fault tolerance features to ensure maximum uptime. They also offer excellent scalability for large enterprises that anticipate significant growth in information storage requirements. And unlike direct-attached storage, excess capacity in SANs can be pooled, resulting in a very high utilization of resources.

Hard Drive Degaussers & Destroyers
from Storage Heaven

There has been much debate in recent times about choosing SAN or NAS in the purchasing decision, but the truth is that the two technologies can prove quite complementary. Today, SANs are increasingly implemented in conjunction with NAS. With SAN/NAS convergence, companies can consolidate block-level and file-level data on common arrays.

Even with all the benefits of SANs, several factors have slowed their adoption, including cost, management complexity and a lack of standardization. The backbone of a SAN is management software. A large investment is required to design, develop and deploy a SAN, which has limited its market to the enterprise space. A majority of the costs can be attributed to software, considering the complexity that is required to manage such a wide scope of devices. Additionally, a lack of standardization has resulted in interoperability concerns, where products from different hardware and software vendors may not work together as needed. Potential SAN customers are rightfully concerned about investment protection and many may choose to wait until standards become defined.

Conclusion

With such a variety of information storage technologies available, what is the best way to determine which one is right for your organization? DAS, NAS and SAN all offer tremendous benefits, but each is best suited for a particular environment. Consider the nature of your data and applications. How critical and processing-intensive are they? What are your minimum acceptable levels of performance and availability? Is your information sharing environment localized, or must data be distributed across the enterprise? IT professionals must make a comprehensive assessment of current requirements while also keeping long-term business goals in mind.

Like all industries, storage networking is in a constant state of change. It's easy to fall into the trap of choosing the emerging or disruptive storage technology at the time. But the best chance for success comes with choosing a solution that is cost-correct and provides long term investment protection for your organization.