- ONTAP 9
- Clustered Data ONTAP 8.3
- Clustered Data ONTAP 8.2
When a SnapMirror relationships is created and updated (either manually or via a schedule) a new snapshot is created on the Source volume. This snapshot is the most recent snapshot in the volume and will be used as base snapshot for the transfer. The SnapMirror engine will then identify the differences between the new base snapshot and the last replication snapshot that was created for the previous transfer (referred to as the "common base snapshot"). These differences are then transferred over to the Destination volume. This data can include data blocks, user files, snapshot copies, LUNs, and other data within the volume. When the transfer is complete, the latest snapshot in the volume is now the "common base snapshot" until the next update is triggered.
SnapMirror requires the common base snapshot to exist on both the Source and Destination volumes for updates.
If not, the operation will fail with a 'No common snapshot' error.