Synchronization with synchronous mode volume groups

Full synchronization

If the volumes in a Remote Copy group have never been synchronized, a full synchronization begins when the group is started. The length of time for the synchronization to complete depends on:

  • the size of the volumes

  • the amount of data the volumes contain, if they are not fully provisioned virtual volumes

  • the size of the replication links

  • the rate of new host writes to the virtual volumes in the group

Resynchronization

To resynchronize synchronous mode volume groups, Remote Copy copies the I/O directly from the primary base volume.

When synchronous mode volume groups are stopped, Remote Copy creates snapshots of the volume groups. When these volume groups are restarted, Remote Copy uses the snapshots to resynchronize the primary and secondary volume groups. The length of time for the resynchronization to complete depends on:

  • how much data changed on the virtual volumes in the group from the time the group suspended

  • the speed of the replication links

  • the rate of new host writes to the virtual volumes in the group