FreeBSD 5.3p6-5.4RC3, Supermicro X6DHR-8G, Dual 3.6GHzXeons,Adaptec aic7902 SCSI interface doesn't work in UP kernel

Ade Lovett ade at
Mon Apr 25 20:06:20 PDT 2005

Guy Helmer wrote:

Reducing the problem to its relevant parts:

> SuperMicro [...] Seagate [...] 
> on-board aic7902 

and, from your dmesg output:

da0: <SEAGATE ST373207LC 0003> Fixed Direct Access SCSI-3 device
da0: 320.000MB/s transfers [...]

Supermicro boards and Seagates generally hate each other.  Supermicro
blames Seagate, Seagate blames Supermicro.  Even under normal operation,
you'll see spurious SCSI errors, both at bootup, and under load,
exacerbated if you put more than one Seagate drive on the same chain, or
run them at their native U320 speeds.

To make matters worse, your ST373207LC model is, even by Seagate
standards, a piece of unmitigated crap.

At an absolute minimum, have the existing drive swapped out for an
ST373453LC model, making VERY certain that the firmware is rev 0006 --
prior revisions WILL corrupt your data, set fire to your cat, and
otherwise ruin your entire life -- and that's before they've actually
spun up.

A second option is to change the drive out for one from a vendor that
actually cares -- ok, maybe only *just* cares, but cares nonetheless.
Hitachi drives work fine, and certainly seem to be in the same ballpark
for overall reliability.

Likewise, swapping out the motherboard for a non-Supermicro unit may be
an option, though be wary of anything with onboard Broadcom gigabit
ethernet if you plan on doing continuous high network I/O -- Seagate
drives *appear* to have considerably fewer problems when connected to
non-Adaptec hardware in general, and the onboard Supermicro variant in

If you're stuck with the hardware you have (modulo this particular 73GB
drive model, as mentioned above), pick up another SCSI controller and
use that, not forgetting to disable the onboard controllers.

At an absolute pinch, head in to the adaptec bios and lock down the
drive to U160 speeds -- that *may* help in a few edge cases.

Someone (I forget who, sorry) recently suggested a considerable
portition of the  Supermicro vs Seagate mess was down to a weird
interaction between the bios and the occasional SMM interrupt -- a
hackaround to run at boot was even suggested -- check the archives for
details, though unfortunately it did not appear to fix the issues I was
seeing on boxes here.  You may have better luck.


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