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Stripe Size HP DL380G5 / P400 for SQL 2005

 
Dickyjoe
Occasional Visitor

Stripe Size HP DL380G5 / P400 for SQL 2005

Hi

I am trying to fix some performance issues with a DL380G5. The machine has 4 internal SAS disks. They are connected to the P400 storage controller with a 512MB BBWC.

The machine is running Windows 2003R2 SP2. The disks have the default allocation unit size of 4096 bytes (disk over 2049MB see http://support.microsoft.com/kb/314878 ).

SQL 2005 stores data in a thing called an extent which is 64kilobytes. A lot of performance docs say to setup paritions for SQL databases with a allocation unit size of 64kilobytes. It does say that you should check with your storage vendor to make sure it stills applies in that environment.

The basic idea is when SQL is writing data to an extent it should be able to do it in one write rather than multiple writes (or laps of the disk).

Has anyone tried this with a proliant DL box and if they have what was it like? Did you see any performance increase. A few websites I have seen say they see increases upto about 40%.

Check out the following msdn article for more info.

http://msdn.microsoft.com/en-us/library/dd758814.aspx

Help.....

Richard
1 REPLY
Dickyjoe
Occasional Visitor

Re: Stripe Size HP DL380G5 / P400 for SQL 2005

Hi again

One thing I forgot to mention is that the 4 SAS disks are 2x72GB 15K and 2x147GB 10K. The disks are setup for Mirroring.

Another thought I had overnight was that the default Stripe size is 128kb and that is the disk partition is aligned and the Windows allocation unit size is 64K then all should be well. Well that is the thought anyone?

Richard