SQL Server Performance

snap shot time calculation

Discussion in 'SQL Server 2005 Database Mirroring' started by contactjimmyus, Sep 23, 2008.

  1. We have a mirrored database with 55 gb in size .We wish to know how much time it will take to make snap shot of the DB .If we are making snap shot at real time mirroring, Does it affect the mirroring session(We are using full safety with out witness server) The average transaction log backup in an hour comes up to 100 mb
  2. satya Moderator

    Me personally haven't tried to attempt the SNAPSHOT backup while mirroring is ON.But looking at how snapshot works:...underlying backup technology creates an instantaneous copy of the data that is being backed up. The instantaneous copying is typically accomplished by splitting a mirrored set of disks or by creating a copy of a disk block when it is written. This preserves the original. ....it should work and shouldn't disturb mirroring.
  3. gurucb New Member

    It should be instantenous as Snapshots use sparse files. Intially even for a 1 TB file snapshot is only going to be in KB. Only on modification of original data, it gets copied to snapshot file.

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