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Tasks to perform for off-host processing

Following is the typical sequence of tasks that must be performed to use IBC Messaging for off-host processing:

1. Prepare the Secondary for off-host processing. For example, create snapshot plexes on the data volumes on the Secondary (prefreeze task).
2. Register an application name for sending and receiving IBC messages on the Primary and the Secondary. Prepare to receive the IBC message on the Secondary.
3. Quiesce the application on the Primary (quiesce task).
4. Send the IBC message from the Primary to the Secondary.
5. Unquiesce the application on the Primary (unquiesce task).
6. Perform the off-host processing task on the Secondary after the Secondary receives the IBC message and replication freezes (onfreeze task). Note that the updates to the Secondary data volume is frozen while the off-host processing task is in progress.
7. Unfreeze the Secondary after the off-host processing task completes.
8. Perform additional tasks on the Secondary after replication has resumed. For example, reattaching the snapshot volumes to the original data volumes on the Secondary (postfreeze task).
9. Unregister the application on both the Primary and the Secondary.

The single command vradmin ibc can be used to perform this sequence of tasks. To use the vradmin ibc command, you need to provide scripts named prefreeze, quiesce, unquiesce, onfreeze, postfreeze to perform the tasks in step 1, step 3, step 5, step 6, and step 8 respectively. The vradmin ibc command uses these scripts with IBC Messaging to perform these tasks in sequence. For more information about the user-defined scripts, see Understanding the scripts used for the vradmin ibc command.

You can also use the vxibc commands to perform off-host processing operations. For details on using the available vxibc commands, see Using the In-band Control Messaging utility vxibc and the IBC programming API.