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Re: QLogic PTI firmware



Mark Morgan Lloyd wrote:

What's acceptable cabling practice on this: it's been set up hung off a single controller with the two halves daisy-chained. Cables are Sun or (decent) IBM and it's a Sun differential terminator, I see no failures if the job count is <=4 (but I continue testing this- it's useful extra heat).

I think it's worth noting explicitly that there's 12x CPUs in this system. I note (but don't see as directly relevant) that the controller won't load the firmware during startup, has to be done by a manual rmmod/modprobe.

Chris, I think some thing from you vanished into the spambin at about 20:30. Please could you resend it to the address below.

"My previous message said that best practice with SBUS is to use only half of the D1000 per controller channel. 6 fast drives is about the max that you can expect the bus speed limited controller to handle without congestion under heavy loads.

I can cope with limited performance, there's times when having plenty of slots into which arbitrary drives can be plugged (e.g. to fix a dud SILO) can be really useful. Having said which, I note that the A1000/D1000 "Just The Facts" explicitly shows the possibility of having both halves of the box connected to a single host controller.

"OTOH, it seems that Linux may not be handling congestion as gracefully as Solaris."

Indeed. In fact, it doesn't appear to be "picking up the pieces" particularly successfully.

toss_command:
        printk(KERN_EMERG "qlogicpti%d: request queue overflow\n",
               qpti->qpti_id);

        /* Unfortunately, unless you use the new EH code, which
         * we don't, the midlayer will ignore the return value,
         * which is insane.  We pick up the pieces like this.
         */
        Cmnd->result = DID_BUS_BUSY;
        done(Cmnd);
        return 1;
}

I'm still working on it to see if I can track it down to a single drive or a particular slot in the rack.

Patrick, thanks for your comment about the firmware being at linux-2.6/firmware/qlogic/isp1000.bin.hex in the standard (i.e. non-Debian) kernel.

--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]


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