panic: ffs_valloc: dup alloc
Uwe Doering
gemini at geminix.org
Tue Mar 14 08:55:21 UTC 2006
Eric Anderson wrote:
> I get the above panic after nfs clients attach to this nfs server and
> being read/write ops on it after an unclean shutdown. I've fsck'ed the
> fs, and it marks it as clean, but I get this every time. It's an NFS
> share of a GEOM stripe (about 2TB).
> mode = 0100600, inum = 58456203, fs = /mnt
> panic: ffs_valloc: dup alloc
Do you happen to have disk mirroring on this server (RAID 1)? At work,
on a workstation with RAID 1, we once had a case where after a power
failure fsck would succeed, but subsequently, when mounting and using
the partitions, the kernel still paniced because of a corrupt
filesystem. Repeatedly.
This caused some major head scratching on our part until we figured out
what was happening. The mirrored disks had gone out of sync. For
performance reasons, a RAID 1 controller reads data from one disk drive
or the other, depending on which drive is less busy in that particular
moment. So while fsck was able to find and fix some filesystem
inconsistencies there were still some more left in disk sectors it
didn't access.
The RAID controller we used turned out to have a verification mode where
it would scan the disks and re-synchronize them. Afterwards we did
another fsck run, and this fixed the remaining filesystem
inconsistencies. The kernel panics were gone.
Now, with the information you've provided I can't tell whether these
findings apply to your case, but perhaps this story helps at least
others in a similar situation.
Uwe
--
Uwe Doering | EscapeBox - Managed On-Demand UNIX Servers
gemini at geminix.org | http://www.escapebox.net
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