What are Delta Block snapshots?
FastBack Delta snapshots only backup data that has changes since the last successful snapshot.
Delta Block snapshots are a hybrid type of snapshots. The entire length of the volume is being read by the FastBack Client in the same manner as for a Full snapshot. However, only the blocks that have changed since the last successful snapshot are being backed up.
Delta Block snapshots cannot be initiated by the user, they are executed by the FastBack automatically
In the following cases:
1) The Client machine has restarted unexpectedly
2) Cluster volumes have failed over from one node to another
3) FastBack Client service is restarted on a Cluster node
4) FastBack Client service has restarted unexpectedly (rarely)