scsi errors only when writing to Promise disks

[Justin T. Gibbs]

> I have just joined this list in an attempt to try and get some guidance
> as to what might be wrong or at least maybe where to turn for help, as
> I don't seem to be getting very far with RedHat.  And Google searches
> on the errors or the particular Promise raid system lead nowhere.

Hmm.  I thought the Promise problems were well known.  Are you running
the absolute latest firmware for your RAID array?  It seems that at
least some versions of these controllers fail to send the last CRC of
a transaction if the transaction is "too large".  You won't see this
under Windows since the largest transaction size is ~128K for disks.
With the aic7xxx driver under Linux, the transaction size can be much
larger.  If you cannot get a fix out of Promise (which I think they have
been able to provide for other models), you can modify the "max_sectors"
variable in the driver's scsi template to be something like 256.  This
should prevent any large I/Os that will trip up your RAID array.  This
value is set near the bottom of the file:

/usr/src/linux/drivers/scsi/aic7xxx/aic7xxx_osm.c

It is currently 8192.

--
Justin