Date: Sun, 26 Sep 2010 20:46:51 +0200 From: Niklas Saers <niklas@saers.com> To: Scott Long <scottl@samsco.org> Cc: freebsd-scsi@freebsd.org, Jakob Jensen <jj@danskscanning.dk>, =?iso-8859-1?Q?michael_Kj=F8gx?= <mk@danskscanning.dk>, =?iso-8859-1?Q?Dag-Erling_Sm=F8rgrav?= <des@des.no> Subject: Re: mfi - setting up disks Message-ID: <4EF4B99C-8550-4207-BBDB-391CF4F2D940@saers.com> In-Reply-To: <EAB77787-6A80-43AC-B979-91262FB18D05@samsco.org> References: <2EA9CBBC-3F97-4AF2-BFB5-96DF39FDE376@saers.com> <86aan67obp.fsf@ds4.des.no> <EAB77787-6A80-43AC-B979-91262FB18D05@samsco.org>
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Hi Scott & Dag-Erling, On Sep 26, 2010, at 1:25 AM, Scott Long wrote: > 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. Indeed, "mfiutil locate" gave us all we needed for identifying the disk, = so numbering is no longer an issue. Thanks for the tip on how to get the = disk back up, I'll make sure we try that this week. I tried the let-the-RAID-controller-make-RAIDs-and-join-them-via-ZFS = model on the mpt-based controller, and that made performance drop from = ~250 mb/sec to ~4 mb/sec. With mfi (the system is otherwise unchanged), = the average speed is ~200 mb/sec, down ~50 mb/sec. Cheers Nik=
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