Virtual disk read/write permissions
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.
Virtual disk copy restrictions
Before you perform any virtual disk copy tasks, understand and adhere to the restrictions listed in this section. The restrictions apply to the
source virtual disk, the target virtual disk, and the storage array.
•
While a virtual disk copy has a status of In Progress, Pending, or Failed, the source virtual disk is available for read I/O activity only. After
the virtual disk copy is complete, read and write I/O activity to the source virtual disk are permitted.
•
A virtual disk can be selected as a target virtual disk for only one virtual disk copy at a time.
•
A virtual disk copy for any virtual disk cannot be mounted on the same host as the source virtual disk.
•
Windows does not allow a physical disk letter to be assigned to a virtual disk copy.
•
A virtual disk with a Failed status cannot be used as a source virtual disk or target virtual disk.
•
A virtual disk with a Degraded status cannot be used as a target virtual disk.
•
A virtual disk participating in a modification operation cannot be selected as a source virtual disk or target virtual disk. Modification
operations include the following:
– Capacity expansion
– RAID-level migration
– Segment sizing
– Virtual disk expansion
– Defragmenting a virtual disk
NOTE:
The following host preparation sections also apply when using the virtual disk copy feature through the CLI
interface.
Creating a virtual disk copy
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.
The Virtual Disk Copy premium feature includes these items:
•
The
Create Copy Wizard
, which assists in creating a virtual disk copy
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Premium feature—virtual disk copy
