Wednesday, August 6, 2008

Disk Alignment?

I attended the Orlando PASS meeting last night where we had 2 speakers. Dolores Tofel, a local and regular attender, who did a short presentation on using Microsoft Access as a UI for SQL Server data. Even though I have developed a distaste for Access, she did a good job showing how it can be used as a RAD tool, particularly for reporting. Andy Warren, president of OPASS, is trying to give local speakers a boost by giving them an opportunity to do a mini-presentation and not be the main draw for the meeting.

The main speaker for the evening was Amy Styers from EMC. She does performance consulting for EMC customers running Microsoft products (SQL Server, Exchange, Sharepoint). Her topic was the top ten ways to improve your SQL Server performance, and I have to admit that most of the list were practices I was already familar with. But, her #10 was new to me and I think to majority of the ~20 folks in attendance. It was to get your disks aligned. She showed us that because the Master Boot Record is 63 k and the tracks are 64k. Basically this means that you will regularly have to do 2 IOs per read or write because you have to cross tracks. Apparently you can see up to a 20% IO performance gain by aligning your partitions. Of course to do this on a production system is a BIG deal as you have to make sure you have good backups and totally wipe your disks. Then you can use the DISKPAR or DISKPART(Windows Server 2003 sp1) to align the partitions and then reformat. Apparently Windows Server 2008 no longer has this issue. Linchi Shea has done some testing of this and posted the results on his blog, here. There is another article here, that deals with the same issue for Exchange with reference to an HP whitepaper. I found this subject very interesting as I had never heard this before and neither had the server admin at my workplace. We don't have any overburdened servers at this time so we won't be making the change, but it is still good to know about in case I meet someone who may be able to do something with it.

This is one reason I go to the user groups meetings even when the featured presentation may not be something I think I'll be using. Last meeting was about SQL Server Mobile and I am using it now for a personal project when I never thought I would before the meeting. I find that I learn something new every meeting and I have a good time meeting other SQL Server specialists.

The next OPASS meeting is scheduled for September 9th, 6:00pm at End to End Training, just outside Orlando. If you are going to be in the area come join us. The featured speaker is going to be great. How do I know that? It's ME! I'll be presenting on SQL Profiler Basics and I think you'll get something from I it. I know I have in preparing for it. If you do come, plan on joining us for the after event as well for some informal geek talk.

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