ad0 READ_DMA TIMEOUT errors on install of 7.0-RELEASE

[Jeremy Chadwick]

On Wed, Feb 27, 2008 at 01:20:50PM -0700, Scott Long wrote:
> I'd like to attack these driver problems.  What I need is to spend a
> couple of days with an affected system that can reliably reproduce the
> problem, instrumenting and testing the driver.  I have a number of
> theories about what might be going wrong, but nothing that I'm
> definitely sure about.  If you are willing to set up your system with
> remote power and remote serial, and if we knew a reliable way to
> reproduce the problem, I could probably have the problem identified and
> fixed pretty quickly.

Scott, I just wanted to take a moment to publicly thank you for stepping
up to the plate on this one.  I have a feeling that most of these
reports will have to be dealt with on a case-by-case basis, but despite
that, I really do apprecaite you offering to take this one.  Thank you
very, very much.

In regards to my experience with said problem, I haven't been able to
reproduce the errors I saw on January 25th:

http://lists.freebsd.org/pipermail/freebsd-stable/2008-January/040013.html

I do need to get the box in question into our datacenter and set up our
remaining dev/test box to do nothing but hard I/O between ZFS and UFS
for hours (or days) on end to see if I can reproduce it.  There's an
entry in the FreeBSD ZFS wiki about this problem, but there's a
possibility the issue I saw is different than what another user reported
(his result was a panic, my result was a machine that locked up hard
after letting FreeBSD report DMA errors for some time).  That user's
post is here:

http://lists.freebsd.org/pipermail/freebsd-stable/2008-January/040047.html

-- 
| Jeremy Chadwick                                    jdc at parodius.com |
| Parodius Networking                           http://www.parodius.com/ |
| UNIX Systems Administrator                      Mountain View, CA, USA |
| Making life hard for others since 1977.                  PGP: 4BD6C0CB |