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Possible Causes of Database Corruption

  • June 29, 2015 at 3:48 pm

    #302126

    Over the weekend, we found SQL Server log entries that showed corrupted log files and later a corrupted database (results from CHECKDB). I've never been the lucky recipient of a corrupted database before so I had to do some digging. Everything I've turned up from Googling around says hardware / Disk I/O problems are the most likely cause of something like this.

    Since this only affected a little used table that could be rebuilt, I was told to repair it and allow the data loss. What I'd like to know is, from your experiences, what has been the culprit in the database corruption you've seen in the past? Has anyone seen this caused by anything other than hardware (disk controller, SAN, etc) or have you seen other causes? The network guys said they don't see any issues in the SAN log or the VM.

    I'm trying to leave no stone unturned before talk to management.

    Environment:

    SQL Server 2012 Enterprise Edition 11.0.3000

    24GB RAM / 4 cores

    Windows Server 2008 R2 Datacenter SP1 on VMWare

    32GB RAM / 8 cores

    Thanks for any insight you can pass my way.

  • June 30, 2015 at 1:27 am

    #1808987

    99%+ IO subsystem.

    That can be anything from a filter driver to the HBA drivers, switch firmware, cables, controllers, SAN cache, disks and everything in between.

    Make sure drivers and firmware is up to date, make sure the cache is correctly configured and battery-backed

    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

  • June 30, 2015 at 9:10 am

    #1809179

    Thanks Gail. I appreciate hearing from your experience on this.

  • July 1, 2015 at 9:42 am

    #1809575

    Agree with Gail. Could be memory, but unlikely. Most likely it's something in the IO system.

  • July 1, 2015 at 10:44 am

    #1809605

    Thanks Steve. Much appreciated.

  • July 7, 2015 at 10:57 pm

    This was removed by the editor as SPAM

  • July 8, 2015 at 8:54 am

    #1810988

    Thanks Prett. I'm glad that my understanding of this aligns with the experts.

    I now have the backup I need to take to the networking team.

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