I attended the March OPASS meeting last night, March 11. The speaker was Kendal Van Dyke and the subject was Performance Impact of Disk Configuration (partition offset, stripe size, and allocation unit size). Kendal had the opportunity to use some hardware at work to run some tests for testing the effects of properly aligning your direct attached storage and the effects of different stripe sizes and allocation units on RAID 1, RAID 1o, and RAID 5 arrays. It was a highly technical, but interesting session. I have to admit that it was a little over my head as I am not a RAID expert, although I do understand how it works. I've always been in a position where I have had a system administrator that has handled configuring my storage, most recently according to my recommendations. The basic theme was that properly aligning your disks, with a 64 kb partition offset will provide about a solid 10% or more performance improvement. Kendal's tests also showed that, for direct attached storage, a 64 kb offset, 64 kb stripe size, and 64 kb allocation unit size was the best overall configuration for performance for an OLTP system. You can see all the results of his tests on his blog as he has a 7 part series detailing his tests starting with this post. If you are interested in more here are a some other resources relating to disk alignment from Linchi Shea, TechNet, and Denny Cherry.
I have to say that I was disappointed with the turnout. We had about 15, possibly because we met on a Wednesday instead of our usual Tuesday, but still disappointing. I was "lucky" enough to get tagged in a discussion going around a group of regular SQL bloggers about "Things I Wish I Had Known" and a common theme in most of the posts was that we wish we had gotten involved in the community sooner. One of the main reasons is because you get the opportunity to learn something on a regular basis and you also get to interact with some really smart people. I know that since I have been attending I have learned a lot about SQL Server, professionalism, and professional development, and mostly from conversations before and after the actual meetings. Last night about half the attendees stayed for at least 30 minutes after the meeting and Kendal, Andy Warren, and I had a great discussion until a little after 10pm. These are the reasons I go to meetings, events like SQLSaturday, and, hopefully, the PASS Summit this fall.