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Jason Horner
Asked: 2009-09-18 07:58:30 +0800 CST

Benefit of Defragging SQL Server Data files located on a SAN

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In the past, I have used contig.exe to remove physical fragmentation from SQL Server data files. They have always been on locally attached storage. Is there any benefit to running this on a data file that is stored on a SAN?

sql-server

1 Answers

  1. Best Answer

    Not recommended to defragment files on a SAN, SQL or otherwise.

    See this related ServerFault question and this excellent whitepaper. The major points include:

    • Defragmenting is very I/O intensive
    • Defragmenting doesn't always improve performance on logical volumes
    • Defragmenting is definitely not recommended for certain specific configurations, like Virtual Storage Pools and Replicated Volumes
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