PE2650 / Perc 3Di crash

Salyzyn, Mark mark_salyzyn at
Tue Aug 5 09:13:18 CDT 2003

If this is the case ... AAC_NUM_IO_FIB defined in
drivers/scsi/aacraid/aacraid.h which was originally set to 512, and is
reduced to 116 in the 2.4.19 generic variant of the driver might have to be
reduced. The 2.4.20 driver has this value *increased* to 512 (!!!!)

In Adaptec's release of the driver it is reduced to a value of 100, only
because we determined experimentally that 128 would crash the adapter, and
100 did not under all test circumstances for a sample of card variants. I
have *no* idea where the 116 came from in the . The theoretical maximum in
the adapter is 512 with *one* array including the RAID splitting and other
Firmware tasks which have to absorb some of the spares above this limit.

My suggestion is to drop the AAC_NUM_IO_FIB to 100, *maybe* 116, but *not*
leave it at 512.

Sincerely -- Mark Salyzyn

Value of AAC_NUM_IO_FIB for various kernels:

2.4.18-14 512
2.4.18-24.7.x 512
2.4.18-24.8.0 512
2.4.18-26.7.x 512
2.4.18-26.8.0 512
2.4.18-27.7.x 512
2.4.18-27.8.0 512
2.4.18-3 116
2.4.18-5 116
2.4.18-e.12 512
2.4.18-e.25 512
2.4.18.SuSE 116
2.4.18.generic 116
2.4.19.SLES 116
2.4.19.SuSE 116
2.4.19.generic 116
2.4.20-13.7 512
2.4.20-13.8 512
2.4.20-13.9 512
2.4.20-18.7 512
2.4.20-18.8 512
2.4.20-18.9 512
2.4.20-6 512
2.4.20-8 512
2.4.20-9 512
2.4.20.SuSE 512
2.4.20.generic 512
2.4.21-rc2-ac2 512
2.4.21-rc5-ac1 100
2.4.21.generic 512
2.4.22-pre6-ac1 100
2.4.9-31.22ml 116
2.4.9-34 116
2.4.9-38 116
2.4.9-e.3 116
2.4.9-e.5 116
2.4.9-e.8 116
2.4.9-e.9 116
2.4.9-e.10 116
2.4.9-e.12 116
2.4.9-e.16 116
2.4.9-e.23 512
2.4.9-e.24 512
2.4.9-e.25 512
2.5.70.generic 100
2.5.74.generic 100
2.6.0-test2 100

-----Original Message-----
From: James Bourne [mailto:jbourne at]
Sent: Tuesday, August 05, 2003 9:43 AM
To: Matthias Pigulla
Cc: linux-poweredge at; linux-aacraid-devel at;
matt_domsch at
Subject: Re: PE2650 / Perc 3Di crash

On Tue, 5 Aug 2003, Matthias Pigulla wrote:

> Hello everyone,
> tonight, I lost one of my PowerEdge boxes with a kernel panic. I'm
> running a PERC 3/Di, RAID10, on Debian woody with a custom 2.4.19
> kernel. I'll try to provide all information I can collect, I hope
> someone can help me to track this issue down. Please bear with me,
> although if it's long :)

FYI, this is what we have seen on our aacraid systems under heavy I/O
and CPU load.  It's unclear at this time if this is a firmware issue
or a driver issue, but I do know that now Dell and Adaptec are working
on a resolution...

Turning off write caching will provide a work around, although you
will still get timeouts, it looks as though the crashes will be prevented.

James Bourne

James Bourne, Supervisor Data Centre Operations
Mount Royal College, Calgary, AB, CA

"There are only 10 types of people in this world: those who
understand binary and those who don't."


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