Take the following procedure to set the system disk mirroring:
1) Checking the partition configuration of the system disk
2) Setting the system disk mirroring
3) Checking system disk settings
4) Checking physical disk information and the slice numbers
5) Collecting backups of the system disk
6) Backing up EFI configuration information
Note
Backing up system disk
Data backed up before system disk mirroring cannot be restored back to the mirrored system disk.
If the system disk mirroring is once canceled and then configured again, you cannot restore the backed up data of the system disk that was collected when the system disk was mirrored previously.
For these reasons, make sure to collect the backed up data of the system disk if the system disk mirroring is configured.
Also make sure to collect the backed up data of the system disk again if the system disk mirroring is configured again.
