slowdown of zfs (tx->tx)

[Nicolas Rachinsky]

Hallo,

after replacing one of the controllers, all problems seem to have
disappeared. Thank you very much for your advice!

> >> On Tue, Jan 8, 2013 at 9:42 AM, Nicolas Rachinsky
> >> <fbsd-mas-0 at ml.turing-complete.org> wrote:

* Artem Belevich <art at freebsd.org> [2013-01-09 17:15 -0800]:
> On Wed, Jan 9, 2013 at 8:26 AM, Nicolas Rachinsky
> <fbsd-mas-0 at ml.turing-complete.org> wrote:
> > * Artem Belevich <art at freebsd.org> [2013-01-08 12:47 -0800]:
> >> You seem to have some checksum errors which does suggest hardware troubles.
> >
> > I somehow missed these. Is there any way to learn when these checksum
> > errors happen?
> 
> Not on FreeBSD (yet) as far as I can tell. Not explicitly, anyways.
> Check /var/log/messages for any indications of SATA errors. There's a
> good chance that there was a timeout at some point.

There is an UDMA_CRC_Error_Count of 17 and 20 for the two disks with
checksum errors. The other disks have values between 0 and 5.

And yes, there have been timeouts some time ago. Since the problem did
occur without the timeout occuring again, I considered the timeouts to
be unrelated. And then I forgot them. :(


But shouldn't timeouts either produce correct data after a retry or
a read/write error otherwise? 


Nicolas
-- 
http://www.rachinsky.de/nicolas