9.1-stable: ATI IXP600 AHCI: CAM timeout

[Oliver Fromme]

Steven Hartland wrote:
 > Have you checked your sata cables and psu outputs?
 > 
 > Both of these could be the underlying cause of poor signalling.

I can't easily check that because it is a cheap rented
server in a remote location.

But I don't believe it is bad cabling or PSU anyway, or
otherwise the problem would occur intermittently all the
time if the load on the disks is sufficiently high.
But it only occurs at tags=3 and above.  At tags=2 it does
not occur at all, no matter how hard I hammer on the disks.

At the moment I'm inclined to believe that it is either
a bug in the HDD firmware or in the controller.  The disks
aren't exactly new, they're 400 GB Samsung ones that are
several years old.  I think it's not uncommon to have bugs
in the NCQ implementation in such disks.

The only thing that puzzles me is the fact that the problem
also disappears completely when I reduce the SATA rev from
II to I, even at tags=32.

Best regards
   Oliver


-- 
Oliver Fromme,  secnetix GmbH & Co. KG,  Marktplatz 29, 85567 Grafing
Handelsregister:  Amtsgericht Muenchen, HRA 74606, Geschäftsfuehrung:
secnetix Verwaltungsgesellsch. mbH, Handelsreg.: Amtsgericht München,
HRB 125758, Geschäftsführer:  Maik Bachmann,  Olaf Erb,  Ralf Gebhart

FreeBSD-Dienstleistungen/-Produkte + mehr: http://www.secnetix.de/bsd

"People still program in C.  People keep writing shell scripts.  *Most*
people don't realize the shortcomings of the tools they are using because
they a) don't reflect on their workflows and they are b) too lazy to check
out alternatives to realize there is help." -- Simon 'corecode' Schubert