Attention:
Possible loss of data – Source logical drives that are participating in a VolumeCopy are available for read I/O activity only while a VolumeCopy has a status of In Progress or Pending. Write requests are allowed after the VolumeCopy has completed.If the source logical drive has been formatted with a journaling file system, any attempt to issue a read request to the source logical drive might be rejected by the storage subsystem controllers, and an error message might appear. The journaling file system driver will issue a write request before it attempts to issue the read request. The controller will reject the write request, and the read request might not be issued due to the rejected write request. This condition might result in an error message appearing, which indicates that the source logical drive is write protected.
To prevent this issue from occurring, do not attempt to access a source logical drive that is participating in a VolumeCopy while the VolumeCopy has a status of In Progress. Also, make sure that the Read-Only attribute for the target logical drive is disabled after the VolumeCopy has completed to prevent error messages from appearing.
Use the to copy data from one (the ) to another logical drive (the ) in a single . You can use this premium feature to copy data from that use smaller capacity to arrays that use larger capacity disk drives. You also can use this premium feature to back up data or to restore data to the . This premium feature includes these items:
You must enable the VolumeCopy premium feature by purchasing a from your storage vendor.
The following sections briefly describe some applications for the VolumeCopy premium feature.
As your storage requirements for a logical drive change, use the VolumeCopy premium feature to copy data to a logical drive in an array that uses larger capacity disk drives within the same storage subsystem. This premium feature lets you perform these functions:
The VolumeCopy premium feature lets you create a backup of a logical drive by copying data from one logical drive to another logical drive in the same storage subsystem. You can use the target logical drive as a backup for the source logical drive, for system testing, or to back up to another device, such as a tape drive.
If you need to restore data to the base logical drive from its associated flashcopy logical drive, use the VolumeCopy premium feature to copy data from the flashcopy logical drive to the base logical drive. You can create a VolumeCopy of the data on the flashcopy logical drive, and then copy the data to the base logical drive.
Attention:
Possible loss of data – If you are using the Windows 2000 operating system or the Linux operating system, use the VolumeCopy premium feature with the FlashCopy premium feature to restore flashcopy logical drive data to the base logical drive. Otherwise, the source logical drive and the target logical drive can become inaccessible to the host.A VolumeCopy fails all flashcopy logical drives that are associated with the target logical drive, if any exist. If you select a base logical drive of a flashcopy logical drive, you must disable all of the flashcopy logical drives that are associated with the base logical drive before you can select it as a target logical drive. Otherwise, the base logical drive cannot be used as a target logical drive.
A VolumeCopy overwrites data on the target logical drive and automatically makes the target logical drive read-only to hosts.
If eight VolumeCopies with a status of In Progress exist, any subsequent VolumeCopy will have a status of Pending, which stays until one of the eight VolumeCopies completes.
If a is running on a source logical drive or a target logical drive, and the VolumeCopy has a status of In Progress, Pending, or Failed, the VolumeCopy does not take place. If a modification operation is running on a source logical drive or a target logical drive after a VolumeCopy has been created, the modification operation must complete before the VolumeCopy can start. If a VolumeCopy has a status of In Progress, any modification operation does not take place.
The Create Copy Wizard guides you through this process:
When you have completed the wizard dialogs, the VolumeCopy starts, and data is read from the source logical drive and written to the target logical drive.
Operation in Progress icons appear on the source logical drive and the target logical drive while the VolumeCopy has a status of In Progress or Pending.
For more information about source logical drives and target logical drives, see the “Restrictions” section that follows.
A VolumeCopy can fail due to these conditions:
When the VolumeCopy fails, a critical event is logged in the Event Log, and a Needs Attention icon appears in the Subsystem Management Window. While a VolumeCopy has this status, the host has read-only access to the source logical drive. Read requests from and write requests to the target logical drive do not take place until the failure is corrected by using the Recovery Guru.
During a VolumeCopy, the same controller must own both the source logical drive and the target logical drive. If both logical drives do not have the same preferred controller when the VolumeCopy starts, the ownership of the target logical drive is automatically transferred to the preferred controller of the source logical drive. When the VolumeCopy is completed or is stopped, ownership of the target logical drive is restored to its preferred controller. If ownership of the source logical drive is changed during the VolumeCopy, ownership of the target logical drive is also changed.
You must manually change controller ownership to the alternate controller to allow the VolumeCopy to complete under all of these conditions:
After you create a VolumeCopy with the Create Copy Wizard, you can monitor the VolumeCopy through the . From the Copy Manager, a VolumeCopy may be re-copied, stopped, or removed. You also can modify its attributes, including the copy priority and the target logical drive Read-Only attribute. You view the status of a VolumeCopy in the Copy Manager. Also, if you need to determine what logical drives are involved in a VolumeCopy, use the Copy Manager or the .
Use the Set Target Logical Drive Read-Only Attribute option to determine how read requests from and write requests to the target logical drive are handled after a VolumeCopy is complete, or if the VolumeCopy fails prior to completing. After the VolumeCopy is complete, the target logical drive automatically becomes read-only to hosts. Write requests to the target logical drive do not take place. When the Read-Only attribute for a target logical drive is enabled, a lock icon appears in the Target Logical Drive column of the Copy Manager. You can change the Read-Only attribute in the Copy Manager only after the VolumeCopy is completed.
Use the Re-copy a Logical Drive option to create a new VolumeCopy of the data on a selected . Use the Re-Copy a Logical Drive option to create a new VolumeCopy from the beginning if the original VolumeCopy fails or was stopped. You can also use this option for backup purposes. For example, if the data on the source logical drive changes, you can use the Re-Copy a Logical Drive option to duplicate any new data to the target logical drive.
Use the Stop a VolumeCopy option to stop a VolumeCopy with a status of Pending, In Progress, or Failed. If you decide not to use a particular logical drive as a source logical drive or a target logical drive, you can use this option to stop the VolumeCopy before it completes. You can then use the logical drives in a new VolumeCopy. Using this option on a VolumeCopy with a status of Failed clears the Needs Attention condition on the storage subsystem.
Use the Change Copy Priority option to balance I/O activity with VolumeCopy activity on a storage subsystem. You can set the copy priority to a rate that will have the least impact on I/O activity. There are five copy priority rates available: lowest, low, medium, high, and highest. If the copy priority is set at the lowest rate, I/O activity is prioritized, and the VolumeCopy takes longer. If the copy priority is set to the highest priority rate, the VolumeCopy is prioritized, but I/O activity for the storage subsystem might be affected.
Use the Remove Copy Pairs option to remove a VolumeCopy from the Copy Manager. After the VolumeCopy is removed, the source logical drive and the target logical drive can be used in a new VolumeCopy. When the VolumeCopy is removed, the Read-Only attribute for the target logical drive is also removed.
These restrictions apply to the source logical drive, the target logical drive, and the storage subsystem:
Important:
If the source logical drive is a primary logical drive, the capacity of the target logical drive must be equal to or greater than the of the source logical drive.
Important:
If you choose a base logical drive of a flashcopy logical drive as your target logical drive, you must disable all flashcopy logical drives that are associated with the base logical drive before you can select it as a target logical drive. Otherwise, you cannot use the base logical drive as a target logical drive.Logical drives that have these statuses cannot be used as a source logical drive or a target logical drive: