The ABCs of SANs for DBAs in Visual Studio .NET

Create QR Code in Visual Studio .NET The ABCs of SANs for DBAs

The ABCs of SANs for DBAs
QR Code ISO/IEC18004 Creator In Visual Studio .NET
Using Barcode creator for .NET Control to generate, create QR Code JIS X 0510 image in .NET applications.
www.OnBarcode.com
Recognize QR Code In Visual Studio .NET
Using Barcode decoder for .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
By now you should have the concept of RAID safely under your belt to the point that you could sit down with a member of your server team and talk a bit of shop. If you did, you will probably find that most of your servers will not have enough drive bays for all the different flavors of RAID that you might desire. You may even find yourself asking for different RAID configurations that result in conversations around external storage . . . and then someone, somewhere, will mention the following: SAN. SAN stands for storage area network, and will either be the most wonderful thing you can possibly imagine (high probability) or a nightmare (not likely, but possible). The concept behind a SAN is quite simple: bundle together hundreds of physical disks,
UCC.EAN - 128 Maker In .NET Framework
Using Barcode generator for VS .NET Control to generate, create EAN / UCC - 14 image in .NET applications.
www.OnBarcode.com
Make 1D Barcode In VS .NET
Using Barcode printer for Visual Studio .NET Control to generate, create 1D Barcode image in .NET applications.
www.OnBarcode.com
CHAPTER 3: Some Basics
Draw Code 128A In Visual Studio .NET
Using Barcode creation for .NET Control to generate, create Code 128B image in .NET framework applications.
www.OnBarcode.com
Printing Code 39 In VS .NET
Using Barcode printer for .NET framework Control to generate, create Code 3 of 9 image in .NET framework applications.
www.OnBarcode.com
partition them out in logical units (called LUNs), and connect your servers to the LUNs for their storage. Figure 3 7 shows how one SAN can serve many servers.
Creating EAN-13 In Visual Studio .NET
Using Barcode creation for .NET framework Control to generate, create GTIN - 13 image in .NET framework applications.
www.OnBarcode.com
ITF Creation In .NET
Using Barcode creation for VS .NET Control to generate, create 2 of 5 Interleaved image in Visual Studio .NET applications.
www.OnBarcode.com
Figure 3 7. Drives in a SAN can be assigned to many servers as needed.
QR Code JIS X 0510 Creator In None
Using Barcode drawer for Microsoft Word Control to generate, create QR-Code image in Microsoft Word applications.
www.OnBarcode.com
Encode QR In Objective-C
Using Barcode printer for iPad Control to generate, create QR Code image in iPad applications.
www.OnBarcode.com
This way, if you needed to add additional storage to a server, it would be as easy as assigning some additional LUNs. In fact, most of the time, all your SAN administrator is going to ask you is, How much space do you need now, Bob No need to swap out smaller drives for larger ones and let your RAID controller rebuild your array. Sounds wonderful, right Maybe. Let s imagine for a moment that you are the SAN administrator. You have hundreds of disks bundled together into LUNs. Which RAID level would you use for all these disks If you answered RAID 5 for its cost-effectiveness and large storage volume, then you may have a future in SAN administration when your DBA days are over. Chances are your SAN is indeed configured with RAID 5. If you recall, RAID 5 is not always ideal for a database server. Don t panic: when used correctly in a SAN, RAID 5 arrays may not be ideal, but they can still be good enough.
Make PDF 417 In VB.NET
Using Barcode encoder for .NET Control to generate, create PDF417 image in Visual Studio .NET applications.
www.OnBarcode.com
Reading Barcode In .NET
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Why RAID 5 Might Work for You
Print QR Code In None
Using Barcode creation for Software Control to generate, create Quick Response Code image in Software applications.
www.OnBarcode.com
Code128 Generation In None
Using Barcode creator for Office Excel Control to generate, create Code 128 image in Office Excel applications.
www.OnBarcode.com
The first reason not to fear is that SAN controllers have built-in cache: memory that serves as a buffer between your server and its storage arrays. Whenever SQL Server issues writes to your drives, they re considered committed as soon as the data enters the SAN controller s cache. When configured correctly, that cache is faster than any drive arrays, whether they re RAID 5 or RAID 10. While your SAN may be at RAID 5, your data is not going to disk directly; it gets dumped into cache first and then goes to disk. Your queries do not wait for it to get to disk; they think it is already there when in fact it is actually still in cache. You see no performance issues until such time as you would actually fill your cache, in which case you have performance issues everywhere, not just on one server.
Barcode Encoder In VB.NET
Using Barcode generation for .NET Control to generate, create Barcode image in .NET framework applications.
www.OnBarcode.com
Recognize EAN 13 In Visual Basic .NET
Using Barcode reader for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
CHAPTER 3: Some Basics
Make PDF417 In Java
Using Barcode drawer for Java Control to generate, create PDF417 image in Java applications.
www.OnBarcode.com
Encode PDF-417 2d Barcode In None
Using Barcode creator for Font Control to generate, create PDF 417 image in Font applications.
www.OnBarcode.com
The second reason you should not panic is because you may have not seen any actual performance problem yet. Just because your SAN may be at RAID 5 is not enough reason to raise the hairs on your back. No sir, you had better be able to provide some proof that you are seeing performance issues that could be related to SAN performance.
Encode GS1 - 12 In None
Using Barcode generator for Excel Control to generate, create UPC A image in Excel applications.
www.OnBarcode.com
EAN / UCC - 13 Encoder In Objective-C
Using Barcode drawer for iPhone Control to generate, create EAN128 image in iPhone applications.
www.OnBarcode.com
The Lost Art of Benchmarking
The only way to find out for certain if storage is a bottleneck before a server goes into production is to do some benchmarking. One thing I find common in most shops these days is that fact that benchmarking is far from a common practice. People tend to slap things together, throw them into production, and wait to see if anyone screams. If you want to make the leap to being Mr. Right, then you will be wise to benchmark some of the more important processes in your shop. That way, when someone says, This is slow, you can quickly reference the latest benchmark to determine if it really is slow or if it is just perception. The first question you need to ask you SAN administrator when troubleshooting possible SAN performance issues is, What is the expected I/O throughput for our SAN Get whatever details you can, and then go back to your cube and start gathering your own metrics. Then compare to see if the expected throughput is close enough to the observed. If not, now you can go back to the SAN administrator with some actual facts. Believe me, that will get you a lot more traction than making a blanket statement such as, We would like to have some space on the SAN carved out in RAID 10 for our tempdb. Unless you have proof that there is a performance issue, your SAN administrator is not going to be compelled to start carving out different RAID levels, even if you know what works best for SQL Server. TIP: The more benchmarking and testing you perform, the more control you have over your environment. Your SAN could indeed be a performance bottleneck, and it may be very difficult for you to troubleshoot. Much in the same way that people will blame a database server because it is a big black box they do not understand, I have seen some DBAs be frustrated because their SAN is also a big box that they do not understand. The best advice I could give to you is to think of your SAN as being a constant. It should serve up a standard I/O throughput. It should allow for you to dynamically add space to a server when needed. It should be the same for each server. And that means you can perform some benchmarks on different servers, assume that the SAN performance should be equal, and take your results to the server team to discuss the discrepancies. It may indeed be the SAN, but it could also be something else.
Copyright © OnBarcode.com . All rights reserved.