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Recover from disk crash

  • October 22, 2009 at 3:19 am

    #211327

    Hi Folks

    Today has been a fun day with our SAN partially crashing and I'm looking for a few suggestions on what my next steps should be after it's recovered.

    Effectively what has happened is the drive/s on our SQL server where the data files reside became disconnected while the server was running. Log files were still available on a separate drive. After the disk crash some users were still processing transactions apparently but I can't verify this. I could certainly query some parts of the database but I'm assuming the buffer cache was fulfilling these queries and most queries usually resulted in error. Thankfully my log shipping was working a treat and my backup server is up to date with the last log shipped should I need it.

    What have I done so far:

    1. Disconnected all users

    2. Backed up the transaction log of the affected databases to potentially roll forward to my backup server or recover the production box.

    3. Shutdown the SQL server while SAN repairs are in progress.

    What likely problems will I see and how should I treat them. I'm planning on running a CHECKDB to see if any problems exist.

    Any ideas would be appreciated.

    Thanks

  • October 22, 2009 at 9:47 am

    #1069502

    Once the san repairs are 'finished', check the windows event log, make sure there are no IO-related errors. Make sure you know where your backups are, in case you need them.

    Start SQL, check the SQL error log and make sure there are no errors in there relating to IO or starting up the databases. Check that the restart-recovery finishes without any errors

    Run checkDB on all of the databases (including the system databases).

    DBCC CHECKDB (<Database Name>) WITH NO_INFOMSGS, ALL_ERRORMSGS

    If you have any errors at all at any point either post them here (if you're willing to wait for free support) or call Microsoft's customer support people if you want immediate assistance at a price.

    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

  • October 22, 2009 at 4:46 pm

    #1069703

    Thanks for the reply Gail

    We're back up and running now, all checks done and no problems or data loss anywhere 🙂

  • November 4, 2009 at 9:55 pm

    #1075136

    there is no data loss.

    thanks,

    santosh

  • November 5, 2009 at 7:58 am

    #1075358

    santoshrachamalla (11/4/2009)

    there is no data loss.

    thanks,

    santosh

    And what brought you to this decision??

    -- You can't be late until you show up.

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