On May 31, 2012, at 9:45 AM, Antonio S. Cofiño wrote: > Markus, > > After Jim's answer I have started to read bout the well known issue. > >> Is it just mpt causing the errors or also mpt_sas? > > Both drivers are causing the reset storm (See my answer to Jim's e-mail).
No. Resets are corrective actions that occur because of command timeouts. The cause is the command timeout. >> General consensus from various people: don't use SATA drives on SAS back- >> planes. Some SATA drives might work better, but there seems to be no >> guarantee. And even for SAS-SAS, try to avoid SAS1 backplanes. > > In the Paul Kraus's answer it mentions that Oracle support says (among other > things) >>> 4. the problem happens with SAS as well as SATA drives, but is much >>> less frequent >> > > That means, that using SAS drives it will reduce the probability of the issue > but no guarantee exists. I have seen broken SAS drives crush expanders/HBAs such that POST would not run. Obviously, at this point there is no OS running, so we can't blame the OS or drivers. I have a few SATA disks that have the same affect on motherboards. I call them, the "drives of doom" :-) >> General consensus from various people: don't use SATA drives on SAS back- >> planes. Some SATA drives might work better, but there seems to be no >> guarantee. And even for SAS-SAS, try to avoid SAS1 backplanes. > > Yes, may be the 'general consensus' is right but 'general consensus' said me > to use hardware based raid solutions. But I started to do 'risky business' > (as some vendors told me) using ZFS and have ended discovering how robust is > ZFS for this kind of protocol errors. "hardware" RAID solutions are also susceptible to these failure modes. > From my complete naive point of view it appears more a issue with the HBA's > FW than a issue with SATA drives. There are multiple contributors. But perhaps the most difficult to overcome is the fundamental differences in the SAS and SATA protocols. Let's just agree that SATA was not designed for network-like fabrics. -- richard -- ZFS Performance and Training richard.ell...@richardelling.com +1-760-896-4422
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