Friday, October 21, 2005


> Our system is backed up to tape each night. Unfortunately our Sys Eng
> is on holidays and I do not know how to recover from tape.

> Could you walk me through it please.

There are lots of ways to do it. Without knowing which your system
admin chose, it's really hard to give you any useful information.

The most likely thing is that you need to use something like
"mt -f /dev/rmt/0n asf 2" to move to file #2 on the tape (the
number 2 is just a random number picked; you'll have to determine
where the backup of the filesystem you need is located on the
tape and use that number instead). Then you'd change to some
directory (like /tmp or some place with lots of space) and do
a "ufsrestore ivf /dev/rmt/0n". Then use "cd", "ls", and "pwd"
to navigate, "add" and "delete" to select which files to extract,
and "extract" (whose prompt you should answer with "1") to extract
them from the tape. Oh, and then "mt -f /dev/rmt/0n offline" to
rewind and eject the tape.

Of course, this assumes that the administrator chose to use ufsdump
to back up the files, which is definitely not a given. Also, it is
quite possible that the administrator chose to do incremental
backups, so if that is the case, you may need to restore from a full
backup tape *and* an incremental backup tapem, which makes things
even more complicated. It's really hard to know what the right
thing to do is without knowing what backup scheme the administrator
chose for that system.


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