When you make a , you make a that has a and a on the same .
The source virtual disk is the virtual disk that contains the data you want to copy. The source virtual disk accepts the host I/O activity and stores the data until it is copied to the target virtual disk. The source virtual disk can be a , a , or the source virtual disk of a snapshot virtual disk. When you start a virtual disk copy, all data is copied to the target virtual disk, and the source virtual disk permissions are set to read-only until the virtual disk copy is completed.
After the virtual disk copy is completed, the source virtual disk becomes available to host applications for write requests. The target virtual disk automatically becomes read-only to , and write requests to the target virtual disk are rejected. To prevent error messages, do not attempt to access the involved source virtual disk while the virtual disk copy is in progress.
Note:
After the virtual disk copy has completed, you can change the Read-Only attribute for the target virtual disk. To change the Read-Only attribute, click the Modify tab, and then click the Manage virtual disk copies link.