SQL Server Performance

mirroring states

Discussion in 'Getting Started' started by lara99, Oct 5, 2009.

  1. lara99 New Member

    hi is there an instance in mirroing with high availability mode, that database or server state goes in cannot server the database.lara
  2. FrankKalis Moderator

    Have you found a solution in the meantime?
  3. satya Moderator

    In high-availability mode, you need all the three server roles: principal, mirror, and witness. In this mode, the transaction safety level is set to FULL. As a result, the data transfer mechanism between the principal and mirror servers is synchronous. That is, the principal server waits for an acknowledgement from the mirror server that the transaction log record has been recorded on the mirror server. Then, the client application gets confirmation that the transaction is committed. If the principal server becomes unavailable, the witness server and the mirror server will form a quorum and perform automatic failover. In addition to automatic failover, you can manually perform the failover. Because the transaction safety level is set to FULL, you do not lose any committed transactions in the event of a failover.

Share This Page