Practice at H3 for Metro Global Mirror

This topic describes how to practice at the remote site (H3) while running a Metro Global Mirror session.

About this task

To practice on the remote site, you first need to suspend the back-end. For example, if running in an H1->H2->H3 configuration, issue a Suspend H2H3 command to pause the Global Mirror portion of the session while leaving the Metro Mirror portion of the session active. When the session is in a suspended state (that is, H2H3 is suspended while in an H1->H2->H3 configuration), you have the option to issue a Recover H3 command.

The Recover H3 command acts differently than other recover commands. In this case, the command acts only to make the remote site (H3) target-available and does not switch the application site to H3. The application site remains the original host site and the session acts as it does in a normal Metro Mirror Failover/Failback session.

While the session is in this mode, it remains capable of disaster recovery at Site 2 and will freeze all pairs to maintain consistency during an error. You can also suspend the session by command and recover to Site 2 if necessary. However, if recovering to Site 2 in this mode, it will not be possible to restart a full three-site solution. To get three sites back up and running, you need to copy back to H1 using the Start H2->H1 command and then suspend and recover to H1. Once H1 is the application host again, you can issue the Start H1->H2->H3 command to restart three-site support. If this is done, all data written to H3 during the practice is overwritten with the data that is on H1.