For the most part, the way you manage disk units with remote mirroring is the same as how you manage disk units with standard mirroring. When you add disk units, unprotected disk units must be added in pairs, as with general mirroring. To achieve remote protection of all added units, half of the new units of each capacity of disk unit should be in the remote group and half in the local group. Single device-parity protected units may be added to disk pools using remote mirroring. However, the disk pool is not protected against a site disaster.
You will also see some differences when you Restore remote mirrored protection after a recovery.
Restore remote mirrored protection after a recovery
To restore mirrored protection following the recovery procedures, you need to perform the following steps:
- Obtain and physically attach all required disk units.
- Stop or suspend mirrored protection if it is currently configured on the system.
- Add the new disk units to the correct disk pools.
- Resume mirrored protection
For detailed information about how to recover systems with mirrored
protection, see Backup
and Recovery 
.