The SnapManager for Hyper-V application’s VSS client sets up the shadow copy set. The VSS client gathers information about what shares to include in the shadow copy set and provides this information to ONTAP. A set might contain one or more shadow copies, and one shadow copy corresponds to one share.

For every share included in the shadow copy set, ONTAP creates a shadow copy and makes the shadow copy writable.

After ONTAP creates the shadow copies, they are exposed to SnapManager for Hyper-V so that the application’s VSS writers can perform automatic recovery.

During the shadow copy set creation, there is a period of time when active changes are occurring to the files included in the backup set. The application’s VSS writers must update the shadow copies to make sure that they are in a completely consistent state prior to backup.

The VSS client notifies ONTAP after it completes automatic recovery. The shadow copy set is made read-only and then is ready for backup. When using SnapManager for Hyper-V for backup, the files in a Snapshot copy become the backup; therefore, for the backup phase, a Snapshot copy is created for every volume containing shares in the backup set. After the backup is complete, the shadow copy set is removed from the CIFS server.