prestartfcconsistgrp

Description

This command prepares a consistency group (a group of FlashCopy mappings) to subsequently start. The preparation step ensures that any data that resides in the cache for the source volume is first flushed to disk. This step ensures that the FlashCopy target volume is identical to what has been acknowledged to the host operating system as having been written successfully to the source volume.

You can use the restore parameter to force the consistency group to be prepared even if the target volume of one or more mappings in the consistency group is being used as a source volume of another active mapping. In this case the mapping restores as shown in the lsfcmap view. If the restore parameter is specified when preparing a consistency group where none of the target volumes are the source volume of another active mapping, then the parameter is ignored.

You must issue the prestartfcconsistgrp command to prepare the FlashCopy consistency group before the copy process can be started. When you have assigned several mappings to a FlashCopy consistency group, you must issue a single prepare command for the whole group to prepare all of the mappings at once.

The consistency group must be in the idle_or_copied or stopped state before it can be prepared. When you enter the prestartfcconsistgrp command, the group enters the preparing state. After the preparation is complete, the consistency group status changes to prepared. At this point, you can start the group.

If FlashCopy mappings are assigned to a consistency group, the preparing and the subsequent starting of the mappings in the group must be performed on the consistency group rather than on an individual FlashCopy mapping that is assigned to the group. Only stand-alone mappings, which are mappings that are not assigned to a consistency group, can be prepared and started on their own. A FlashCopy consistency group must be prepared before it can be started.