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

CAUTION: Possible loss of data—Source virtual disks that are participating in a virtual disk copy are available for read I/O activity only while a virtual disk copy has a status of In Progress or Pending. Write requests are allowed after the virtual disk copy has completed. If the source virtual disk has been formatted with a journaling file system, any attempt to issue a read request to the source virtual disk may be rejected by the storage array, and an error message may appear. The journaling file system driver issues a write request before it attempts to issue the read request. The storage array rejects the write request, and the read request may not be issued due to the rejected write request. This condition may result in an error message appearing, which indicates that the source virtual disk is write protected. To prevent this issue from occurring, do not attempt to access a source virtual disk that is participating in a virtual disk copy while the virtual disk copy has a status of In Progress. Also, make sure that the Read-Only attribute for the target virtual disk is disabled after the virtual disk copy has completed to prevent error messages from appearing.