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Date: Tue, 29 Jun 2004 09:51:05 -0400
From: "Kevin A. Pieckiel" <pieckiel+freebsd-questions@sdf.lonestar.org>
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Subject: Snapshot question
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Greetings!

I use filesystem snapshots when I backup my filesystems.  I backup to tape
and I ALWAYS read back the backup and compare it to the snapshot to verify
the data was written correctly.

I use FreeBSD 5.2.1-p6, and my tape drive is an Exabyte M2 drive.

When I do my compare of my tape against my snapshot, it's not uncommon for
one or two files (always the same files) to be different.  The most usual
culprit being my winbindd_cache.tdb file for Samba.  I thought the snapshot
would not change over time as the files on the filesystem change.  Does this
definitively indicate this particular file isn't being written to tape
correctly most nights?  (Yes, I *AM* backing up my snapshot and comparing
the backup to my snapshot, not the live filesystem.)

I doubt it, since I've gotten differences in this file on four different
tapes, all brand new.  What does this mean?  Is there a problem, or am I
missing something?

Thanks,
Kevin