Warning: bad experience with KBackup and 100M zip disks

[Mark Phillips <mark@ist.flinders.edu.au>]

Yesterday was a bad day.  I do a bit of maintenance work for a
friend's laptop.  Yesterday morning he contacted me about problems he
was having booting it.  As it turned out he had accidentally used the
rescue disk to destroy his system.  "Initialize ext2 partition?"  Why
of course!

Fortunately a few weeks back, I had used KBackup to backup all
important files (ie /home and /etc) onto a 100M zip disk.  I would
simply have to reinstall debian and then recover this backup --- or so
I thought.

After a few trials I managed to get was working debian up.  Then came
the time to use KBackup.  It seemed to be going well at first, until I
noticed that with quite a number of files, it was complaining of
corruption.  Most times it seemed to recover from this okay though, or
so it said --- "such and such a file decompressed -- OK" was the final
verdict.

A few if them though it complained of unexpected end of file and these
weren't successful.

Oh well, a few corrupt files, but most of them okay --- that isn't too
bad I thought.  Except that on closer inspection, it seems that an
awful lot of files are corrupted.  Many files are just empty.  Other
files seem to have the odd character missing or something.  It seems
that the warnings about possible corruption, even when it managed to
recover, were really corruptions.

To make matters worse, I noticed that KBackup was doing strange
things.  When it wanted to create, for example, the "Mail" directory,
it also created files "M", "Ma" and "Mai".  These files were just text
files with a bit of blank space in them.

And to top it off, the most serious problem...

I noticed that it hadn't backed up a whole directory trees of files it
was supposed to have.  Under the user "bill"'s home directory, it had
backed up his "Mail" directory, a few .something directories and a few
.files, but all the rest of his directories hadn't been!  I listed the
contents of the archive and these directories simply aren't there!  It
could possibly be a problem with my configuration of KBackup, but I
very much doubt it.  It was supposed to backup whole directory trees,
including /home.

I thought possibly it ran out of space on the zip disk, but surely it
would have warned me, or better still, asked me to insert a new zip
disk?

So, I am still totally mystified about why it went so horribly wrong.
It would seem the KBackup software is at least partly to blame, maybe
entirely to blame?  It uses gzip in conjunction with afio, which I
thought were fairly reliable.  Hardware could possibly be to blame,
but I thought zip disks were fairly reliable these days??

Anyway, the end result is that my friend has lost a lot of stuff.  I
just thought it would be good for me to warn others about my
experience.

I hope the same thing doesn't happen to anyone else out there!

Mark.


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        "They told me I was gullible ... and I believed them!"