Fairly regular crash with usb disk backup

[S. Anthony Sequeira]

Hi,

$ uname -a
FreeBSD corona.sequestor.lan 4.10-STABLE FreeBSD 4.10-STABLE #0: Sat Jul
10 14:24:06 BST 2004    
root at corona.sequestor.lan:/usr/obj/usr/src/sys/CORONA  i386

I have a USB enclosure with a 200 GB disk which I use for backups using
RVM.

4 times out of 5 (approximately) all goes well.  The 5th time it hard
crashes the system.

It's a bit annoying, but I can live with it.  However, I'm sure someone
would like details of the problem.  I am also a bit worried about the
state of my disk volumes after the crash.

There is absolutely nothing in /var/log/messages or redirected stdin/err
for the job.

What, if anything, should I do so as I can provide debugging material if
required?
-- 
Experience is directly proportional to the cost of the equipment ruined.