mirroring intervals for automatic failover

  • Hi,

    in my production server i configured mirroring with automatic fail over in sql server 2008 r2 can anyone tel me how much interval want to set as per standard my database size is 250 gb

  • What do you mean by "Intervals"?

    Mirroring is realtime which means that transactions are committed at both partners in realtime - Depending on your mirroring mode - Synchronous or Asynchronous

  • am asking automatic failover occurred due to network failure means how much time mirror as a principal .

  • Perhaps I'm missing something here but I'm still not sure what you're asking

  • automatic failover occured means principal database go to mirror and mirror database come to principal iam asking how much time take for mirror comes to principal my db size is 250 db

  • Ok - You mean, how long will it take for the Mirror to take over as the Principal

    As far as I know, it should be instant

    Remember that your mirroring session needs to be running in high-safety mode and must have a witness.

    Have a look here

    http://msdn.microsoft.com/en-us/library/ms189590(v=sql.105).aspx

  • i have another question PARTNER TIMEOUT how much to set for automatic fail over for 250 gb database

  • Partner Timeout is more to do with your network latency and how far Mirror and Partner are physically apart from each other - Database size plays little part here

  • but this will play important role in automatic failover right

  • Yes it will

    Principal, Mirror and Witness constantly Ping each other - The Partner Timeout is how long after NOT receiving a reply must it perform an automatic failover. I think the default is 5 seconds..

    If you change the timeout to a high amount, this will compromise how long it will wait to Failover automatically after a problem has occured at your Principal.

  • thanks for your update today my confusion is cleared

  • No Problem

    😎

  • SQLSACT (5/23/2013)


    Yes it will

    Principal, Mirror and Witness constantly Ping each other - The Partner Timeout is how long after NOT receiving a reply must it perform an automatic failover. I think the default is 5 seconds..

    If you change the timeout to a high amount, this will compromise how long it will wait to Failover automatically after a problem has occured at your Principal.

    Actually, default is 10 seconds. Depending on your network you may want to increase this to prevent false fail overs. At a previous employer we increased this time to 30 seconds because at 10 seconds we experienced fail overs due to network issues and our servers were in the same room.

    We had no issues with this setting and if the principal server did go down the 30 second delay was also not a problem.

  • That's why I said "I think..." Wasn't sure - Thanks for clearing up

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