This appendix explains how to use the IBC Messaging command-line utility vxibc and the API for off-host processing. The In-Band Control (IBC) Messaging feature with the Snapshot feature of Veritas Volume Replicator (VVR) and optional FastResync (FR) feature of Volume Manager (VxVM) enable you to perform off-host processing. Typically, to perform off-host processing, you would use the vradmin ibc command to sequence and automate the operations.

See Performing off-host processing tasks.

However, if you want to customize the process beyond what can be achieved by using the vradmin ibc scripts, or if you want to program and integrate off-host processing in your control facility, you need to use the vxibc command or the IBC API.

Off-host processing consists of performing operations on application data on a host other than the one where the application is running. Typical applications include Decision Support Systems (DSS), backup, and trial failover in VVR. In a VVR environment, off-host processing reduces the load on the application server, the Primary, and uses the potentially under-utilized Secondary.

The model for data access on the Secondary is that you break off a mirror from each data volume in the RVG, perform the operation on the mirror, and then reattach the mirror while replication is in progress.