Kernel Panic on Backup

[Norman Elton]

Hello,

We've begun rolling out NFSv4 for our servers. We mainly use it to  
mount home directories for the sysadmins who SSH into the box, as well  
as for a shared "scratch" space. We're not really pushing tons of data  
here.

I have a cron job that backs up relevant directories to the NFS mount  
nightly using rsync:

rsync -rlptD --stats --exclude-from=/etc/backup.conf --exclude='*' / / 
nfs/backup/$HOSTNAME

Everything was working fine for the past few weeks, until I recently  
rebuilt four servers to use NFSv4. Three of these have locked up so  
far, two of which died about the time of the nightly backup. I was  
able to get a picture of the kernel panic on the third server:

http://wnelto.people.wm.edu/crash.jpg

The panic seems to have some scary GSS / NFS messages in there, but  
I'm unsure what to do next.

Any ideas?

Thanks,

Norman Elton
College of William & Mary
Williamsburg VA