Dell EMC PowerVault MD 34XX/38XX Series Storage Arrays Administrator's Guide

After the virtual disk copy is complete, the target virtual disk automatically becomes read-only to the hosts. The target virtual disk rejects read and write requests while the virtual disk copy operation has a status of Pending or In Progress or if the operation fails before completing the copy. Keep the target virtual disk Read-only enabled if you want to preserve the data on the target virtual disk for reasons such as the following:

• If you are using the target virtual disk for backup purposes.
• If you are using the data on the target virtual disk to copy back to the source virtual disk of a disabled or failed snapshot virtual disk.

If you decide not to preserve the data on the target virtual disk after the virtual disk copy is complete, change the write protection setting for the target virtual disk to Read/Write.