Suspending Database Mirroring

  • Hi All

    Does anybody know if suspending db mirroring prevents automatic failover should the primary fail ?

    I know that Suspending stops transactions being sent to the mirror and the principal runs exposed, but would the witness still attempt to failover should the primary become unavailable ?

    Thanks in advance

    Preet

  • I do not believe so.

    Automatic failover requires the following conditions:

    The database mirroring session must be running in high-safety mode and must possess a witness. For more information, see Synchronous Database Mirroring (High-Safety Mode).

    The mirror database must already be synchronized. This guarantees that all of the log sent to the mirror server has been written to disk.

    Automatic Failover

    Joie Andrew
    "Since 1982"

  • No it most certainly will not failover automatically.

  • Preet_S (12/20/2012)


    Hi All

    Does anybody know if suspending db mirroring prevents automatic failover should the primary fail ?

    I know that Suspending stops transactions being sent to the mirror and the principal runs exposed, but would the witness still attempt to failover should the primary become unavailable ?

    Thanks in advance

    Preet

    I believe, suspending mirroring means, it's paused somehow, can be done manually or can cause by many different things.....It can be due to network failure, or space issues.

    Does anyone know what else can cause the mirroring to be in a suspended state?

    SueTons.

    Regards,
    SQLisAwe5oMe.

  • SQLCrazyCertified (12/27/2012)


    Does anyone know what else can cause the mirroring to be in a suspended state?

    SueTons.

    Creating a new file on the principal when the file paths between the principal and the mirror are different

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    "Ya can't make an omelette without breaking just a few eggs" 😉

  • Perry Whittle (12/28/2012)


    SQLCrazyCertified (12/27/2012)


    Does anyone know what else can cause the mirroring to be in a suspended state?

    SueTons.

    Creating a new file on the principal when the file paths between the principal and the mirror are different

    Hi P

    Regards,
    SQLisAwe5oMe.

  • Perry Whittle (12/28/2012)


    SQLCrazyCertified (12/27/2012)


    Does anyone know what else can cause the mirroring to be in a suspended state?

    SueTons.

    Creating a new file on the principal when the file paths between the principal and the mirror are different

    Hi P

    Regards,
    SQLisAwe5oMe.

  • Perry Whittle (12/28/2012)


    SQLCrazyCertified (12/27/2012)


    Does anyone know what else can cause the mirroring to be in a suspended state?

    SueTons.

    Creating a new file on the principal when the file paths between the principal and the mirror are different

    Hi Perry,

    Can u explain what exactly you mean creating a file, are you talking about new ndf file? Please advise with some example if you don't mind.

    SueTons.

    Regards,
    SQLisAwe5oMe.

  • If you have a principal server with database file path "D:\MSSQL\MYDBS" and you create the database file "D:\MSSQL\MYDBS\adventureworks_data2.mdf" and the path does not exist on the mirror, this will cause the mirror session to be suspended.

    This link details that for mirroring to work seamlessly, the file paths should be synchronised between the servers.

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    "Ya can't make an omelette without breaking just a few eggs" 😉

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