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DB MIRRORING

  • April 26, 2011 at 1:56 am

    #148964

    Hi

    I setuped the database mirroring in my organization and.i installed patches to my os .after installing pathces to my os going to be restarted (principle server).and also another system having mirror server it is also going be restarted so what happened to database mirroring .

    either data may be losss...! wht can i do in this situation

  • April 26, 2011 at 2:03 am

    #1315708

    Why do you think data will be lost?

    Reboot the mirror, once it's up, fail the mirroring over, then reboot the principal.

    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

  • April 26, 2011 at 5:16 am

    #1315772

    SUPER SQL STAR (4/26/2011)

    either data may be losss...! wht can i do in this situation

    The chances of data loss is minimal , but it also depends on how you have configured your database mirroring Whether it is in synchronous or asynchronous mode.

    And also because it is a planned activity you must always perform this on mirror first, DB mirroring being a high-Availability solution is meant to provide higher availability and also high protection (Synchronous mode) .

    so, i agree with Gail shaw on switching strategy.

  • April 26, 2011 at 5:58 am

    #1315795

    hey

    thanks for the reply .I setuped the mirroring in

    Synchronized: the databases are fully synchronized.

    so if pathes are installed to my operting syetem.it needs to going to be restarted .so what chance i can save the data

  • April 26, 2011 at 7:56 am

    #1315881

    With synchronous mirroring there is NO chance of losing data. Why do you think there is?

    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

  • April 29, 2011 at 5:57 am

    #1317746

    I've recently done some patching on SQL Server instances which are engaged in a mirroring session. You only need to make sure that the sequence of transaction log on the principal is not broken while re-establishing the mirroring session and the data won't be lost at all. Here is my operation sequence and let's say A is principal and B is mirror.

    Step0. Disable all transaction log backup on A (because log backup while the mirroring session is off will flush the log into backup files and once you try to re-establish the mirroring, log chain will be broken)

    Step1. Stop mirroring session from A and all mirrored databaes on B enter into "restoring" state.

    Step2. Patch A with service pack and reboot it.

    Step3. Patch B with service pack and reboot it.

    Step4. From A, re-make the mirroring session to the target databases on B.

    Step5. Enable all the transaction log backup jobs on A.

    Bazinga!

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