I discovered today that my tape drive was dirty and did not realize it.
What happened was the drive sent a scsi error to the kernel/OS and
somehow the root (/), home (/home), and holding disk area recognized by
AMANDA was changed from rw access to ro access.  I believe this change
was made by AMANDA itself.  This happened while AMANDA was backing up.

I had to reboot the machine to place the ro filesystems back to rw as
they should be.  I then repeated the attempted backup and the failure
occurred again exactly the same way (so it was repeatable).  This is
when I suspected the dirty tape drive.  I cleaned the drive and the
problem went away.  The backups now work like they should (and have for
years).

This is the first time I have seen this.  The drive got dirty due to a
different person changing the tapes did not realize they should also
clean the drive occasionally.  I also have new higher-capacity tapes so
that the same number of tapes will get the driver dirtier quicker.

Does the switch from rw to ro by AMANDA make sense ??  Is this a
"feature" ?  This is first I have heard of this.

-- 
James D. Freels, Ph.D.
Oak Ridge National Laboratory
freelsjd AT ornl DOT gov

"Windmills can't even produce enough energy to manufacture a windmill."
-Ann Coulter, 03/01/07.