If you copied the system disk data while mirroring was active, start up the system in rescue mode from the installation CD of the OS and delete the setup information for system disk mirroring.
See
For the method of deleting it, see "Resolution" of "System cannot be booted. (Failure of all boot disks)" in "System Disk Abnormality [EFI]" of "PRIMECLUSTER Global Disk Services Configuration and Administration Guide."
Note
After the end of the rescue mode in this procedure, when you boot the system, start it up in single-user mode.
This procedure is unnecessary if you carried out cloning with temporarily canceled system disk mirroring.