Kernel GPF

[Bryn M. Reeves]

On Sun, 2010-02-07 at 17:32 -0430, Patrick O'Callaghan wrote:
> After reducing my RAM to 2GB via the mem= boot option (see parallel
> branch of this thread) I don't seem to be getting memory errors, but I
> still have problems, apparently with NFS. I've posted a trace from
> dmesg to http://fpaste.org/eEh6/

That sounds a bit like:

http://article.gmane.org/gmane.linux.nfs/30419

and:

http://article.gmane.org/gmane.linux.nfs/30437

There's a patch in the first link which I don't think is in the kernel
you're running; could be worth a look if you are seeing this regularly.

> The scenario is that I'm using rsync to an NFS-mounted directory as a
> backup method. I had previously tried rsyncing directly to the server
> (an Iomega ix2-200 desktop NAS), but it's unbelievably slow in this
> configuration. I measured 100-300Kbps doing it this way -- which would
> take well over a day to run my initial full backup job), versus at least
> an order of magnitude faster running rsync over NFS. I conjecture that
> the NAS cpu just isn't up to calculating the rsync checksums fast enough
> to keep up with a 100Mbps LAN.

Is the box under memory pressure while doing this workload with mem=2g?
That would tend to support the idea that you're seeing the above problem
since it's been reported to occur under low memory conditions.

Regards,
Bryn.