When you start remote system mirroring, the local disk unit is mirrored
to the remote disk unit. If a site disaster occurs at either the local or
remote location, a complete copy of all data on the system still exists, the
system configuration can be recovered, and processing can continue. To provide
protection against a site disaster, all disk units in all disk pools of the
system must be mirrored in local-remote pairs. Follow these steps to prepare
your system for remote mirroring:
- Plan which optical buses will control disk units at the remote site.
- It is not functionally necessary that the local site and the remote site
use the same number of buses. However, it is simplest to configure and understand
the system if the number of remote and local buses and disk units are equal.
- It is functionally necessary that both the local and remote sites have
the same number of each capacity of disk units in each disk pool.
- Plan the distribution of disk units, move disk units if necessary, and
verify that half of each capacity of disk units in each disk pool is attached
to the local and remote set of buses.
- Indicate to the system which buses control remote disk units and which
buses control local disk units.