Split-volume backup can proceed only if all of the following requirements are met:
The volume set must have been previously initialized as a mirrored volume set through the VOLUTIL utility.
The volume set must be a nonsystem volume set. Currently, only nonsystem
volume sets can be mirrored.
All members of the volume set and both partners of each pair must be present at the time of the split. None of the volumes may be disabled or suspended, or undergoing a repair.
Once the above requirements have been met, you can proceed to back up the mirrored disk data.
