IBM System Storage DS3000, Programming Manual

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Planning to use the data on the target logical drive to copy back to the base logical drive in case of a
disabled FlashCopy logical drive or failed FlashCopy logical drive
At other times, you might want to write additional data to the target logical drive. You can use the
set
VolumeCopy
command to reset the read/write permission for the target logical drive.
Note: If you have set the VolumeCopy parameters to enable host writes to the target logical drive, the
read request and the write request to the target logical drive are rejected while the VolumeCopy
operation has a status of In Progress, Pending, or Failed.
The command takes this form:
set VolumeCopy target [ targetName ] [source [ sourceName ]]
copyPriority=(highest | high | medium | low | lowest)
targetReadOnlyEnabled=(TRUE | FALSE)
Important: Setting the
targetReadOnlyEnabled
attribute to
false
breaks the one-to-one relationship
between the source and target VolumeCopy logical drives. Therefore, any data that are written to the
target VolumeCopy logical drive will not be copied to the source VolumeCopy logical drive. In addition,
these data will be lost if you recopy of the source VolumeCopy logical drive to the target VolumeCopy
logical drive.
Note: You can use the parameters as needed to help define your configuration.
This example shows the
set VolumeCopy
command:
c:\...\...\client>smcli 123.45.67.89 -c “set VolumeCopy
target [\”Obi_1\”] copyPriority=highest
targetReadOnlyEnabled=FALSE;”
This example shows how to use the command in a script file:
set VolumeCopy target [“Obi_1”] copyPriority=highest targetReadOnlyEnabled=FALSE;
Recopying a Logical Drive
Use the
recopy VolumeCopy
command to create a new VolumeCopy for a previously defined copy pair
that has a status of Stopped, Failed, or Completed. You can use the
recopy VolumeCopy
command to
create backups of the target logical drive. Then, you can copy the backup to tape for off-site storage.
When you use the
recopy VolumeCopy
command to make a backup, you cannot write to the source logical
drive while the recopy operation is running. The recopy operation might take a long time.
Restriction: Because of this restriction, IBM strongly recommends using a FlashCopy version of the
logical drive as the source for the VolumeCopy, rather than using the original logical drive as the source.
If you use the FlashCopy as the source for the VolumeCopy operation, then I/O operations to the original
logical drive can continue.
When you run the recopy VolumeCopy command, the data on the source logical drive is copied in its
entirety to the target logical drive.
Attention: Possible loss of data access – The recopy VolumeCopy command overwrites existing data on
the target logical drive and makes the target logical drive read-only to hosts. The
recopy VolumeCopy
command fails all of the FlashCopy logical drives that are associated with the target logical drive, if any
exist.
You can also reset the copy priority by using the
recopy VolumeCopy
command if you want to change the
copy priority for the recopy operation. The higher priorities allocate storage subsystem resources to the
VolumeCopy at the expense of storage subsystem performance.
Chapter 9. Using the VolumeCopy Premium Feature
9-7