Dell PowerVault MD3620f Command Line Interface Manual page 86

Copy priority has five relative settings, which range from highest to lowest.
The highest priority supports the virtual disk copy, but I/O activity might be
affected. The lowest priority supports I/O activity, but the virtual disk copy
takes longer. You can change the copy priority at three different times in
the operation:
• Before the virtual disk copy begins
• While the virtual disk copy has a status of In Progress
• After the virtual disk copy has completed re-creating a virtual disk copy
using the recopy virtualDiskCopy command
When you create a virtual disk copy pair and after the original virtual disk
copy has completed, the target virtual disk is automatically defined as read-
only to the hosts. The read-only status of the target virtual disk ensures that
the copied data on the target virtual disk is not corrupted by additional writes
to the target virtual disk after the virtual disk copy is created. Maintain the
read-only status when the following conditions apply:
• You are using the target virtual disk for backup purposes
• You are copying data from one disk group to a larger disk group for greater
accessibility
• You are planning to use the data on the target virtual disk to copy back to
the source virtual disk in case of a disabled or failed snapshot virtual disk
At other times you might want to write additional data to the target virtual
disk. You can use the set virtualDiskCopy command to reset the read/write
permission for the target virtual disk.
NOTE:
If you enabled host writes to the target virtual disk, read and write requests
are rejected while the virtual disk copy has a status of In Progress, Pending, or
Failed.
The following syntax is the general form of the command:
set virtualDiskCopy target [targetName] [source
[sourceName]] copyPriority=(highest | high |
medium | low | lowest) targetReadOnlyEnabled=(TRUE
| FALSE)
NOTE:
Use one or both of the parameters as needed to help define your
configuration. It is not necessary to use either parameter.
86
Using the Virtual Disk Copy Feature