How do I restore file systems under miniroot?


If a system's root, usr or var file system gets corrupted, the best
way to restore them is to boot the miniroot tape, following the
instructions in the CX/UX System Administration Guide, 0890108-110,
Chapter 3, "Installing Software", and use the latest level 0 dump
tape of the file system created with fdump(1M) to restore from.

At the point in the "Installing Software" procedure displayed at
the bottom of Figure 3-5 on page 3-13, you'll be at the root
prompt '#'.

Create device nodes for the disk and tape drives:

# cd /dev
# ./MAKEDEV gd0
# ./MAKEDEV gd1
# ./MAKEDEV gt0

Note: use 0 or 1 depending on your disk/tape drive numbers.

You may need to recreate the file system. As an example, let's
use /usr, mounted on /dev/dsk/0s2.  First, run newfs to rebuild
the file system and check it with fsck:

# newfs /dev/rdsk/0s2  [must use raw device - see newfs(1M)]
# fsck /dev/rdsk/0s2

Create a temporary mount point, NOT named /usr, and mount it:

# mkdir /tmpusr
# mount /dev/dsk/0s2 /tmpusr

Because the miniroot file system is small, it may become filled
up by the temporary files that are generated during the restore.
Remove all the files in the miniroot's /sbin directory, as these
are not needed during the restore process:

# cd /sbin
# rm *

Note that these files are not permanently removed - they are copies
located in the RAM disk (swap partition) as a result of fastcopy(8).

Now, move to the /tmpusr directory, remove the miniroot tape, insert
the restore tape, and do the restore:

# cd /tmpusr
# restore r

NOTE: If the restore tape has more than one file system on it, you
will have to position the start-of-tape to the location where the
/usr file system was dumped. See restore(1M).