[KLUG Members] IBM ServeRAID problems

[Mike Slack]

Well ... it looks like my problems are solved!  At least I am able to make backups to my DAT drive now without any problems, and I have yet to see any hangs.  Also, as a side benefit, the I/O on the box is significantly faster, too.  Thanks again, Adam.

Mike

-- 
Mike Slack
mike@slacking.org
--
"If we knew what it was we were doing, it wouldn't
be called research, would it?" --Albert Einstein

Mike Slack (mike@slacking.org) wrote:
> Well, what do you know?  It turns out one of the PCI slots on my motherboard (SuperMicro P6SBU) is an Adaptec RAIDport, meaning you can get a special PCI adapter from Adaptec to upgrade the onboard SCSI (PCI) to RAID.  Guess which slot my ServeRAID card was on?  Yep, the RAIDport slot.  So I moved the ServeRAID card and now I have different IRQs for aic7xxx and ips drivers.  We'll see if this works; stress test is in progress as I write.  All in all, I think the prognosis is good.  Adam, thanks.  You always seem to be one I can count on for an answer when all other avenues have dried up.
> 
> I'll report back later when I have completed some tests.
> 
> Mike
> 
> -- 
> Mike Slack
> mike@slacking.org
> --
> "If we knew what it was we were doing, it wouldn't
> be called research, would it?" --Albert Einstein
> 
> 
> Adam Williams (awilliam@whitemice.org) wrote:
> > >This is a response to a response I got about 3 weeks ago.  I've had no time
> > >to look into the details until very recently. I checked /proc/pci and
> > >/proc/interrupts and noticed that the onboard scsi controller and the
> > >ServeRAID controller share an IRQ (this is after various fiddlings with
> > >the BIOS):
> > >$ cat /proc/interrupts
> > >           CPU0       
> > >  0:    4718026          XT-PIC  timer
> > >  1:       1821          XT-PIC  keyboard
> > >  2:          0          XT-PIC  cascade
> > >  5:          0          XT-PIC  es1370
> > >  6:         43          XT-PIC  floppy
> > >  8:     143799          XT-PIC  rtc
> > > 10:      18285          XT-PIC  eth0
> > > 11:      55523          XT-PIC  aic7xxx, ips
> > > 12:       4969          XT-PIC  PS/2 Mouse
> > >NMI:          0 
> > >ERR:          0
> > >(It doesn't look like there are any memory address conflicts of any kind). 
> > 
> > Ok,  nothing falls close?  My memory conflict was non-obvious.  The
> > cyclades port controller and the IPS had diffrent **base** addresses but
> > the cyclades I/O slice was 16k, so it **overlapped** onto the IPS's
> > address space.  Took some very nasty BIOS fiddleing to get around it.  
> > 
> > Don't you LOVE the Intel/PC platform?  So incredibly robust and well
> > designed.....
> > 
> > >I read somewhere that a shared IRQ might cause hangs (even though in theory 
> > >it shouldn't; the problems I am having always occur during I/O
> > 
> > Your right,  PCI should be able to share IRQs.  Depending upon chipsets
> > and how the specific drivers are coded, in actuality, it may or may nor
> > work.  It also doesn't guarantee the best performance.
> > 
> > >intensive operations like tape backups or opening large files, etc.). 
> > >The root partition is mounted on a disk on the onboard controller, and
> > >all other mounts (including /home) are on the ips controller.  Most
> > >peripherals (including tape, CDROM) are on the onboard controller.  So
> > >it looks to me like this is a good candidate for the source of the
> > >problems (they always occur when both controllers are doing intensive
> > >operations).  Unfortunately, I haven't been able to test my theory,
> > 
> > Yep,  you probably develope a nice race condition on a spin-lock/mutex
> > somewhere.
> > 
> > >since I can't seem to set separate IRQs for aic7xxx and ips no matter
> > >what I do.  I can set the ips IRQ from the BIOS, but whatever I set it
> > >to, aic7xxx follows (or doesn't get loaded at all).  Am I missing
> > >something here?  Or is this even something I should be trying?  Any
> > >other suggestions?
> > 
> > Have to tried physically moving the card to a different PCI slot? (I'm
> > serious).  How motherbords allocate resources seems to vary widely. 
> > Your "on board" SCSI controller may simply be a PCI device.  My
> > motherboard seems almost to assign certain IRQs to certain slots no
> > matter what is stuck in them, if a previous one is empty, etc....  Also
> > some PCI slots can't bus-master,  which you really want on a SCSI and
> > network controller.  I've noticed the slots nearer to the "top" of the
> > motherboard (away from any ISA slots) seem to have a "higher" priority.
> > I'm no expert on PCI (by any stretch of the imagination) but I *know* I
> > have fixed weird problems by just moving the cards.
> > 
> > 
> > _______________________________________________
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> > 
> 
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