Creating GAD pairs

Pair creation copies the data in a volume in the primary storage system to a volume in the secondary storage system. A GAD pair is created using volumes in storage systems in the primary and secondary sites. Before a pair is created, the GAD reserve attribute must be applied to the volume that will become the S-VOL.

If you want to use consistency groups to manage pairs, you must specify an option to assign each GAD pair to the appropriate consistency group when you create the pair. For details about storage system support (firmware) for consistency groups, see Requirements and restrictions.

You can create a GAD pair using either of the two procedures: VSM auto-configuration and VSM manual configuration. When you create a GAD pair, if the prerequisites for VSM auto-configuration are met, auto-configuration is executed. If the prerequisites for VSM auto-configuration are not met, VSM manual configuration is executed. For details about the prerequisites for these procedures, see Creating a GAD pair using VSM auto-configuration and Creating a GAD pair using VSM manual configuration.

The following table shows the changes in virtual information items when you create a GAD pair.