When replacing drives in Sun V880s with fiber channel, you must boot the system using
For the new drive to be recognized properly. The Sun SCSI drives that are set up for FibreChannel have a World Wide Name associated with them. If you boot without the "-r", the system looks for the drive under the old WWN and doesn't find it. That makes the fsck fail.
The "-r" flag tells it to rebuild the low level device list during boot. It finds the replacement drive with the new WWN and associates it with the proper /dev/dsk device. The new drive will then mount up properly without additional intervention.