format LUNs with 64 k chunks for sql server

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format LUNs with 64 k chunks for sql server

Mani-584606

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April 3, 2014 at 3:07 pm

#291913

Do we need to consider any parameters before we format LUNs with 64 k chunks for sql server?
Is it always improves performance by formating LUNs with 64 k chunks for sql server?
Do we need do this for both mdf and ndf files or just mdf files?
Thanks

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MyDoggieJessie SSC-Forever Points: 44486 More actions · Answer 1

You should do it for all disks from the initial set up, and most importantly (not sure this still applies for server versions beyond 2008 so you may want to check that) you need to align the disk partitions. This MUST be done before the disks are added to the pool of disks and LUNS are carved out. I don't believe you can do it after-the-fact...

[Quote]An appropriate value for most installations should be 65,536 bytes (that is, 64 KB) for partitions on which SQL Server data or log files reside. In many cases, this is the same size for Analysis Services data or log files, but there are times where 32 KB provides better performance. To determine the right size, you will need to do performance testing with your workload comparing the two different block sizes.[/quote]

Ref: http://technet.microsoft.com/en-us/library/dd758814(v=sql.100).aspx

______________________________________________________________________________Never argue with an idiot; Theyll drag you down to their level and beat you with experience

SQLBuddy123 One Orange Chip Points: 28294 More actions · Answer 2

Mani-584606 (4/3/2014)
Do we need to consider any parameters before we format LUNs with 64 k chunks for sql server?
Is it always improves performance by formating LUNs with 64 k chunks for sql server?
Do we need do this for both mdf and ndf files or just mdf files?
Thanks

Yes it improves performance as SQL Server works with Extents (8 Pages = 64 KB). Do this formatting for all SQL Server Data and Log drives and you should also align your partitions with an offset. All of this has to be done before installing SQL Server.

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SQLBuddy

Mani-584606 SSChampion Points: 11788 More actions · Answer 3

his MUST be done before the disks are added to the pool of disks and LUNS are carved out

I thought, formatting the drives with 64 kb is OS level operation. why we need to do on SAN level?

Thanks