Comments on: SQL Server 2005: Improving performance of Multiple Databases & LUNS http://itknowledgeexchange.techtarget.com/itanswers/sql-server-2005-multiple-databases-luns/ Tue, 21 May 2013 22:12:11 +0000 hourly 1 By: The Most-Watched IT Questions: July 6, 2010 - ITKE Community Blog http://itknowledgeexchange.techtarget.com/itanswers/sql-server-2005-multiple-databases-luns/#comment-78889 The Most-Watched IT Questions: July 6, 2010 - ITKE Community Blog Tue, 06 Jul 2010 06:26:15 +0000 #comment-78889 [...] Bulldog98 asked a great question for last month’s Storage in 2010 about improving the performance of multiple databases & LUNs in SQL Server 2005. Back up Mr. Denny and see if you have anything to add to the [...]

]]> By: bulldog98 http://itknowledgeexchange.techtarget.com/itanswers/sql-server-2005-multiple-databases-luns/#comment-78348 bulldog98 Sun, 20 Jun 2010 10:37:35 +0000 #comment-78348 Thanks for your reply, all the databases are identical, they have different loads at different times and some are busier than others.

From what I’ve been reading, there are suggestions that splitting the *.mdf and *.ndf files across multiple volumes to “stripe” the data can help improve disk performance. As an example I was planning the following:

Let’s say I create 6 volumes with 6 disks each in RAID 10 called I:, J:, K:, L:, M: and N: and I have 4 databases: DB1, DB2, DB3, DB4.

DB1_1.mdf would sit on volume I:, DB1_2.ndf on volume J:, DB1_3.ndf on volume K:, DB1_4.ndf on volume L:, DB1_5.ndf on volume M:, DB1_6.ndf on volume N:.

DB2_1.mdf would sit on volume K:, DB2_2.ndf on volume L:, DB2_3.ndf on volume M:, DB2_4.ndf on volume M:, DB2_5.ndf on volume N:, DB2_6.ndf on volume I:.

DB3_1.mdf would sit on volume L:, DB3_2.ndf on volume M:, DB3_3.ndf on volume N:, DB3_4.ndf on volume I:, DB3_5.ndf on volume J:, DB3_6.ndf on volume K:.

DB4_1.mdf would sit on volume M:, DB4_2.ndf on volume N:, DB4_3.ndf on volume I:, DB4_4.ndf on volume J:, DB4_5.ndf on volume K:, DB4_6.ndf on volume L:.

Would the above configuration changes help to spread the IO load and give us an improvement in IO performance in comparison to the current configuration that we have below: (Both I: and J: in the current configuraiton use 16 disks each in RAID 10).

DB1_1.mdf, DB1_2.ndf, DB1_3.ndf, DB1_4.ndf, DB1_5.ndf, DB1_6.ndf all on volume I:
DB2_1.mdf, DB2_2.ndf, DB2_3.ndf, DB2_4.ndf, DB2_5.ndf, DB2_6.ndf all on volume I:

DB3_1.mdf, DB3_2.ndf, DB3_3.ndf, DB3_4.ndf, DB3_5.ndf, DB3_6.ndf all on volume J:
DB4_1.mdf, DB4_2.ndf, DB4_3.ndf, DB4_4.ndf, DB4_5.ndf, DB4_6.ndf all on volume J:

As for the RAID, I always believed that RAID 5 would save us space and give us the slightly worse read performance and a lot worse write performance than that of RAID 10 due to the parity overheads? and from everything I have read this appears to be the case.

Also, is it best to store the log files on seperate volumes for each of the databases? or would I see little benefit from that? currently all log files from all the databases are stored on a single RAID 10 volume with 10 disks (tempdb is also stored on its own volume).

Many Thanks

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