Subject: ftape format warning!!!

From: Ken Gaugler <[email-masked]>
Date: Mon, 19 Aug 1996 08:16:29 -0700

I had a nasty surprise using ftape to dump my filesystems for archival
right before repartitioning my hard drive.  I wanted to let people
know about this in case they were not already aware.

If you plan to dump several filesystems to one tape (that is, more than
one session on a tape) you need to erase the tape using mt FIRST!!!
Otherwise you will not be able to read any sessions beyond the first.

There were only two sessions on my tape.  Sadly, the second session
contained the /usr filesystem, so I lost everything :(

YMMV
---
Key fingerprint =  D6 A7 D7 8C 92 CB 42 FD  60 D5 62 1C D7 B9 EA 8E 
Ken Gaugler  N6OSK         Hybrid Networks, Inc.  Cupertino, Calif.
URL: www.hybrid.com (home: [email-masked]  URL: users.aimnet.com/~keng)
"The life of a Repo Man is ALWAYS INTENSE..."

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From: [email-masked]
Date: Mon, 19 Aug 96 16:33 EDT

Ken Gaugler writes:
  Ken>  I had a nasty surprise using ftape to dump my filesystems for
  Ken> archival right before repartitioning my hard drive.  I wanted to let
  Ken> people know about this in case they were not already aware.
  Ken> 
  Ken> If you plan to dump several filesystems to one tape (that is, more
  Ken> than one session on a tape) you need to erase the tape using mt
  Ken> FIRST!!!  Otherwise you will not be able to read any sessions beyond
  Ken> the first.

You could have read the Ftape-HOWTO before attempting to do this. It says:

  6.4.  Putting more than one tar file on a tape

  To put more than one tar file on a tape you must have the mt utility.
  You will probably have it already, if you got one of the mainline
  distributions, e.g.  Slackware or Debian.

  tar generates a single Tape ARchive (that's why it is called `tar')
  and knows nothing about multiple files or positioning of a tape, it
  just reads or writes from/to a device. mt knows everyting about moving
  the tape back and forth, but nothing about reading the data off the
  tape.  As you might have guessed, tar and mt in conjunction, does the
  trick.

  By using the nrft[0-3] (nftape) device, you can use `mt' to position
  the tape the correct place (`mt -f /dev/nftape fsf 2' means step over
  two ``file marks'', i.e.  tar files) and then use tar to read or write
  the relevant data.

  Ken> There were only two sessions on my tape.  Sadly, the second session
  Ken> contained the /usr filesystem, so I lost everything :(

Moreover, you can simplify your life by using a program as tob which reads
from several filesystems. Debian tob's package is in the admin section.

--
Dirk Eddelb"uttel                             http://qed.econ.queensu.ca/~edd

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From: Lars Wirzenius <[email-masked]>
Date: Tue, 20 Aug 1996 01:31:53 +0300

> contained the /usr filesystem, so I lost everything :(

Whenever doing backups, _verify_ your backups, even if it doubles the time
it takes to do them.

Oh, and whenever you're going to do something dangerous, _double_ your
backups. It's _not_ funny to try to restore from the backup you verified
yesterday, only to notice that something bad happened a floppy over the
night. Don't ask why I know this.

Using modern floppies (3.5") for backups is not a good anyway, but sometimes
you can't afford a tape drive. Not that tapes don't get errors, too.

If it's worth doing, it's worth doing properly. That applies to paranoia, too.

-- 
Rural sizes win <[email-masked]> <http://www.iki.fi/liw/>
Please don't Cc: me when replying to my message on a mailing list.

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From: [email-masked] (Christoph Lameter)
Date: 19 Aug 1996 17:53:09 -0700

: 
: There were only two sessions on my tape.  Sadly, the second session
: contained the /usr filesystem, so I lost everything :(
Rejoice! you did not lose anything! Just reinstall and restore what you
have. All stuff in usr are executables and other read-only stuff as 
per FSSTND. (except if you had sources in /usr/src or customizations in
/usr/local)