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Rebuild indexes in database after new disks added

  • May 18, 2009 at 6:21 am

    #155718

    Hello,

    This may sound like a silly question, but if a database has been moved to a new set of disks (SAN), would it be a good idea to rebuild all the indexes as a apposed to running indexdefrag?

    I apprieciate pages, extents etc, but wondered if the old underlying disks were fragmented is it recomended that a full reindex is done on the new disks?

    Thanks

  • May 18, 2009 at 6:29 am

    #996262

    Index fragmentation and disk fragmentation are different things. Indexrebuild and index defrag (and the 2 SQL 2005 replacements to them) fix index fragmentation. They are neither affected by nor do they fix disk fragmentation.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass

  • May 18, 2009 at 6:31 am

    #996264

    sqlrumble (5/18/2009)

    Hello,

    This may sound like a silly question, but if a database has been moved to a new set of disks (SAN), would it be a good idea to rebuild all the indexes as a apposed to running indexdefrag?

    I apprieciate pages, extents etc, but wondered if the old underlying disks were fragmented is it recomended that a full reindex is done on the new disks?

    Thanks

    only if you don't normally have a maintenance window to reindex the databases and this database move has given you an opportunity, even then just reindex the indexes that are fragmented.

    by moving the database files to a new drive you ahve removed fragmentation at the drive level.

    Fragmentation within the database (empty pages, extents out of order) is independent of that.

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  • May 18, 2009 at 6:32 am

    #996265

    Gail, stop it! give someone else a chance! 😀

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  • May 18, 2009 at 6:34 am

    #996266

    george sibbald (5/18/2009)

    Gail, stop it! give someone else a chance! 😀

    Type faster in future. 😉

    😛

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass

  • May 18, 2009 at 6:41 am

    #996271

    I think i have started a 'SQL-RUMBLE'.

    Thanks for the responses.

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