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Date:      Sat, 25 Sep 2010 17:25:50 -0600
From:      Scott Long <scottl@samsco.org>
To:        =?iso-8859-1?Q?Dag-Erling_Sm=F8rgrav?= <des@des.no>
Cc:        freebsd-scsi@freebsd.org, Niklas Saers <niklas@saers.com>
Subject:   Re: mfi - setting up disks
Message-ID:  <EAB77787-6A80-43AC-B979-91262FB18D05@samsco.org>
In-Reply-To: <86aan67obp.fsf@ds4.des.no>
References:  <2EA9CBBC-3F97-4AF2-BFB5-96DF39FDE376@saers.com> <86aan67obp.fsf@ds4.des.no>

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On Sep 24, 2010, at 4:45 PM, Dag-Erling Sm=F8rgrav wrote:
> Niklas Saers <niklas@saers.com> writes:
>> In the SuperMicro system where I had problems with the mpt =
controller,
>> I switched it for a mfi-based controller. I had it set up with 36x
>> RAID0 volumes with each their own disk (no way to access the disk
>> otherwise I found), and added them to a ZFS system. The numbering
>> became a bit weird, so I pulled the disks out one by one and put them
>> back to figure out and note down what disk number was in what
>> slot. Only test data on my ZFS volume, so I didn't mind that =
crashing.
>=20
> You can wire down SCSI buses and disks in /boot/device.hints so each
> disk always gets the same device number regardless of the order in =
which
> the disks spin up.  The syntax is documented in /sys/conf/NOTES =
(search
> for "SCSI DEVICE CONFIGURATION").  It's a CAM feature, and mfi uses =
CAM,

MFI only uses CAM for passthrough access to component drives, not for =
normal I/O.  Setting CAM wiring hints will not solve the problem at =
hand.  And the problem at hand isn't really even numbering, it's that =
the MFI firmware freaked out and marked the disks inaccessible.  I think =
that this happened to us at Yahoo once, and we eventually gave up and =
replaced the disks.  Putting the disks on a non-LSI, non-RAID controller =
and writing 0's to the last 10MB worth of sectors (or just writing 0's =
to the entire drive) will likely solve the problem, but YMMV.

Scott





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