SQL 2005 Mirroring Power Loss (No Witness)

  • Hi

    We have a basic SQL Mirroring setup with 2 servers with No Witness or Automatic Failover.

    I have some questions about when either of these 2 servers loses power.

    EXAMPLE 1

    Sever A (Principle)

    Server B (Mirror)

    Server A loses power = What happens to the mirroring on Server B i.e. what state do the databases go into?

    When the power comes back on Server A will Server B start mirroring again i.e. re-sync on it's own? or will something manual have to be done on 1 or both servers and in what order?

    If it's a planned power down should we manually break the mirroring before we take Server A down?

    EXAMPLE 2

    Server B (Mirror)

    Server A (Principle)

    Server B loses power = What happens to the databases on Server A i.e. what state do the databases go into?

    When the power comes back on Server B what needs to be done on Server A and what needs to be done on Server B i.e. does anything happen automatically and what will need to be done manually, and in any particular order?

    If it's a planned power down should we manually break the mirroring before we take Server B down?

    Hope this make sense and thanks in advance for anyone who can help with the answers 🙂

  • In example 1, The principle server goes down and you have no witness so the mirrored databases remain in a restoring state. They can be put online if you need to access them but if you do that you would have to recreate the mirroring when the principle server comes back up. If the principle server comes up and you haven't put the databases online then mirroring will resync and carry on.

    In example 2, The mirror server goes down. The principle server carries on but the transaction log will start to fill. If the mirror server comes up then mirroring will resume and carry on.

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