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SQL Server Mirroring RRS feed

  • Question

  • If when using SQL Mirroring does it replicate both ways

    I.e Server A and Server with Serve A as principal server,
    Server A falls over for whatever reason and B then becomes used server. When A comes back online will Server B replicate all changes to A and will B become the Principal server.

    Friday, August 20, 2010 3:49 PM

Answers

  • Correct.

    All changes are replicated from Principal to Mirrored Partner.  So if Server A is principal it will send all transaction information to Server B.  If a failover takes place and roles switch where as Server B is principal and Server A is mirrored partner; all transactions will be held in Server B until transactions can be set to Server A (assuming it actually went offline).

    Cheers!

    • Marked as answer by ChrisLuther Monday, August 23, 2010 9:23 AM
    Friday, August 20, 2010 9:25 PM
  • HI,

    U r right, When server A comes back online it will assigned the role of Mirror Server and Server B currently [Principle server] replicate all changes to server A in High avaiablilty mode only since two server are need to form quorum (Witness) . But untill server A comes up log cannot be truncated in server B for DB involed in mirroing.

    • Marked as answer by ChrisLuther Monday, August 23, 2010 9:23 AM
    Saturday, August 21, 2010 6:31 AM

All replies

  • Correct.

    All changes are replicated from Principal to Mirrored Partner.  So if Server A is principal it will send all transaction information to Server B.  If a failover takes place and roles switch where as Server B is principal and Server A is mirrored partner; all transactions will be held in Server B until transactions can be set to Server A (assuming it actually went offline).

    Cheers!

    • Marked as answer by ChrisLuther Monday, August 23, 2010 9:23 AM
    Friday, August 20, 2010 9:25 PM
  • HI,

    U r right, When server A comes back online it will assigned the role of Mirror Server and Server B currently [Principle server] replicate all changes to server A in High avaiablilty mode only since two server are need to form quorum (Witness) . But untill server A comes up log cannot be truncated in server B for DB involed in mirroing.

    • Marked as answer by ChrisLuther Monday, August 23, 2010 9:23 AM
    Saturday, August 21, 2010 6:31 AM
  • The following links explains how database mirroring in SQL Server works:

    http://technet.microsoft.com/en-us/library/cc917680.aspx


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    Sunday, August 22, 2010 12:00 PM