Discarding changes to FlashCopy target volumes using DS CLI

Complete this task to discard changes to FlashCopy^® target volumes to form a consistency group on the target volumes as part of a disaster recovery process.

You cannot discard changes to FlashCopy target volumes unless you have modified the FlashCopy relationship using the setflashrevertible command, which changes the Revertible value to Enabled. You can use the revertflash command only when your analysis of the FlashCopy relationships reveals one of the following conditions:

The FlashCopy relationships are revertible and all the sequence numbers are equal.
There is a group of FlashCopy pairs that are all revertible and another group of FlashCopy pairs that are all nonrevertible. In addition, all the FlashCopy sequence numbers are not equal. However, the following conditions exist:
- The FlashCopy sequence number for all revertible pairs is equal.
- The FlashCopy sequence number for all nonrevertible pairs is equal.

If a FlashCopy consistency group formation operation does not complete, you must determine whether to discard changes (revert to a previous consistent state) or commit the operation to the current state. As part of a disaster recovery process, determine the state of the consistency groups in the affected sessions. The Discard Changes task specifies that the previous consistency group that was created by the Global Mirror session becomes the current state, and the Commit Changes task is no longer possible.

The Discard Changes task removes the FlashCopy relationship changes and resets them to the last consistency group state. The revertible state is set to No.

You can perform this task using either the DS CLI or the DS Storage Manager.

Perform the following step to correct the applicable FlashCopy relationships with DS CLI commands. The example command in this task is shown in two formats. The first format shows the type of information that the command requires. The second format is an example command with declared values for the variables.

Issue the revertflash command to correct the FlashCopy relationships and reset them to the last consistency group state. Enter the revertflash command at the dscli command prompt with the following parameters and variables:

dscli>revertflash -dev storage_image_ID SourceVolumeID

Example

dscli>revertflash -dev IBM.1750-68FA150  0100

Notes:

Remember that storage_image_ID is the value for the remote server that has been designated the primary server until the original primary server is again available for use.
Global Mirror operations have performed the establish FlashCopy revertible processing but might have failed to form a consistency group before the disaster occurred. If your analysis, through use of the lsflash command, has determined that a revertflash command is needed, there is no need to issue a new mkflash command.

A confirmation message like the following one is generated for each FlashCopy relationship that has been successfully reset.

FlashCopy pair 0100:0200 successfully reverted to the previous consistency.