Dell PowerVault MD3820f - Manual (Page 32)

• Back up data.
• Copy data from disk groups that use smaller-capacity physical disks to disk groups using greater
capacity physical disks.
• Restore snapshot virtual disk data to the source virtual disk.
Virtual disk copy generates a full copy of data from the source virtual disk to the target virtual disk in a
storage array.
• Source virtual disk — When you create a virtual disk copy, a copy pair consisting of a source virtual
disk and a target virtual disk is created on the same storage array. When a virtual disk copy is started,
data from the source virtual disk is copied completely to the target virtual disk.
• Target virtual disk — When you start a virtual disk copy, the target virtual disk maintains a copy of the
data from the source virtual disk. You can choose whether to use an existing virtual disk or create a
new virtual disk as the target virtual disk. If you choose an existing virtual disk as the target, all data on
the target is overwritten. A target virtual disk can be a standard virtual disk or the source virtual disk of
a failed or disabled snapshot virtual disk.
NOTE: The target virtual disk capacity must be equal to or greater than the source virtual disk
capacity.
When you begin the disk copy process, you must define the rate at which the copy is completed.
Giving the copy process top priority slightly impacts I/O performance, while giving it lowest priority
makes the copy process longer to complete. You can modify the copy priority while the disk copy is
in progress. For more information, see the online help.
Virtual Disk Recovery
You can use the Edit host server-to-virtual disk mappings feature to recover data from the backup virtual
disk. This functionality enables you to unmap the original source virtual disk from its host server, then
map the backup virtual disk to the same host server.
Ensure that you record the LUN used to provide access to the source virtual disk. You need this
information when you define a host server-to-virtual disk mapping for the target (backup) virtual disk.
Also, be sure to stop all I/O activity to the source virtual disk before beginning the virtual disk recovery
procedure.
Using Snapshot And Virtual Disk Copy Together
You can use the Snapshot Virtual Disk or Snapshot Virtual Disk (Legacy) and Virtual Disk Copy premium
features together to back up data on the same storage array, or to restore the data on the snapshot
virtual disk to its original source virtual disk.
You can copy data from a virtual disk in one of the two ways:
• By taking a point-in-time snapshot of the data
• By copying the data to another virtual disk using a virtual disk copy
You can select a snapshot virtual disk as the source virtual disk for a virtual disk copy. This configuration is
one of the best ways you can apply the snapshot virtual disk feature, since it enables complete backups
without any impact to the storage array I/O.
You cannot use a snapshot repository virtual disk as a source virtual disk or as a target virtual disk in a
virtual disk copy. If you select the source virtual disk as the target virtual disk of a virtual disk copy, you
must disable all snapshot virtual disks associated with the source virtual disk.
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