This is a mini-HOWTO on restoring the /, /usr and /var partitions from tapes made with ufsdump. Like procedures apply for other backup media and/or tools.
Boot from Installation CD 1 of 2 in single user mode.
Create a new file system on the partition that holds /usr or /var:
Mount the partition on a temporary directory:
mount /dev/dsk/c0t0d0s3 /a
Change to that temporary directory
Restore from tape:
ufsrestore rf /dev/rmt/0
Remove the restore report:
Leave the temporary directory, unmount the partition.
Run a filesystem check on your restored data:
While in single user mode, take a new backup of this partition.
Execute steps 1-6 of the above scheme.
Change to the directory holding the installboot program for your architecture:
cd /usr/platform/`uname -m`/lib/fs/ufs
Mind that this is /usr on the CD. When you boot from it, you will find yourself initially in /tmp/root.
Install a bootblock on your root partition:
installboot bootblk /dev/rdsk/c0t0d0s0
Execute steps 7-10 of the above scheme.