Re: dell poweredge 2400 harddisks going into offline mode when heavy I/O occurs

[Matt Domsch]

On Tue, Oct 03, 2006 at 10:20:19PM -0400, Bill Davidsen wrote:
> Matt Domsch wrote:
> >On Thu, Sep 28, 2006 at 04:19:23PM +0200, Folkert van Heusden wrote:
> >>Hi,
> >>
> >>I have a Dell Poweredge 2400 with 6 scsi harddisks in (hw-) raid 5.
> >>512MB ram, 2x P3.
> >>When heavy disk i/o occurs, the system puts the harddisks into offline
> >>mode causing the filesystems to be put in readonly. The current kernel
> >>is 2.6.8, with 2.4.27 this did not occure. Googling did not help. The
> >>disks all have green lights (there's a special led for each to indicate
> >>errors - that one is off).
> >
> >[snip]
> >>Sep 28 16:05:12 kasparov kernel: aacraid: Host adapter reset request. 
> >>SCSI hang ?
> >>Sep 28 16:06:12 kasparov kernel: aacraid: SCSI bus appears hung
> >>Sep 28 16:06:12 kasparov kernel: scsi: Device offlined - not ready after 
> >>error recovery: host 1 channel 0 id 0 lun 0
> >
> >Yes, this is familiar. See:
> >
> >http://lists.us.dell.com/pipermail/linux-poweredge/2004-May/014694.html
> >
> >In addition, please consider mounting your file systems with
> >'noatime', as this reduces the number of small writes being sent to
> >the disks.
> >
> >2.6.x kernels have the ability to swamp the RAID controller firmware
> >with requests where 2.4.x kernels couldn't so easily.
> 
> Can you configure the controller as JBOD and use software raid.

Yes, you can.  It's an option in the BIOS SETUP screen during POST.

> Would the controller keep up with that?

Yes.  (This is what I had done on my PE2400 for years too, before I
replaced it entirely).  The SCSI controller is then driven by aic7xxx,
80MB/sec capable, though in that unit it's only a single SCSI channel
and the backplane is a single 1x6 backplane, so you can't split the
bus in half; but that's no different than what you've already got.

Thanks,
Matt

-- 
Matt Domsch
Software Architect
Dell Linux Solutions linux.dell.com & www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com
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