Dell MD3200, MD3220 owner manual Rules and Guidelines for Performing a Snapshot Rollback, 158

The associated snapshot repository virtual disk must have sufficient capacity to process the rollback operation and the write operations from the host. At most, the snapshot repository virtual disk may need twice the size of the base disk, plus additional metadata space equaling approximately 1/1000th (that is, 0.1%) of the Base volume capacity.

NOTE: Due to host server write operations, the content in the snapshot virtual disk may have changed since creation of the snapshot. The rollback operation includes any changes made to the snapshot after it was created.

You can set priority for a rollback operation. Higher priority allocates more system resources for the rollback operation and affects overall system performance.

Rules and Guidelines for Performing a Snapshot Rollback

The following rules and guidelines apply to performing a snapshot rollback:

•Rolling back a base virtual disk to a snapshot virtual disk does not affect the contents of the snapshot virtual disks.

•Only one snapshot rollback operation can be performed at a time.

•While a base virtual disk that is undergoing a rollback, you cannot create a new snapshot virtual disks from that base virtual disk.

•A snapshot rollback cannot be started while any of these operations are underway:

–Virtual Disk Capacity Expansion

–Virtual Disk Expansion (VDE)

–RAID Level Migration

–Segment Size Migration

–Virtual Disk Copy

–Role Reversal (in remote replication)

•If the base virtual disk is a secondary virtual disk in a remote replication, you cannot perform a snapshot rollback.

•If any capacity used in the associated snapshot repository virtual disk contains unreadable sectors, the snapshot rollback fails.

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Configuration: Premium Feature—Snapshot Virtual Disks