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

A virtual disk copy fails all snapshot virtual disks that are associated with the target virtual disk, if any exist. If you select a source virtual disk of a snapshot virtual disk, you must disable all of the snapshot virtual disks that are associated with the source virtual disk before you can select it as a target virtual disk. Otherwise, the source virtual disk cannot be used as a target virtual disk.

A virtual disk copy overwrites data on the target virtual disk and automatically makes the target virtual disk read-only to hosts.

If eight virtual disk copies with a status of In Progress exist, any subsequent virtual disk copy has a status of Pending, which stays until one of the eight virtual disk copies completes.