Re: Accessing SCSI-Devices >2TB

From: Brian Candler <B.Candler_at_pobox.com>
Date: Thu, 9 Jun 2005 14:05:11 +0100
On Thu, Jun 09, 2005 at 11:36:16AM +0200, Raphael H. Becker wrote:
> The first idea was to have just one large logical drive (LD1) with 12 
> physical discs (PD1 - PD12), where P1 is HotSpare. The RAID wants to talk 
> a LBA64 dialect of SCSI AFAIK and FreeBSD isn't able to talk this with 
> the RAID  --> no /dev/daX!

SCSI has always used a Linear (or Logical) Block Address offset from the
start of the disk. What you probably mean is that the controller is issuing
a READ(16) command instead of a READ(10), for example. See the SCSI
documentation: e.g.
http://www.t10.org/ftp/t10/drafts/sbc2/sbc2r16.pdf

Now, setting aside the ccd workarounds for now, IIUC the fundamental problem
is that you cannot attach your drive array when it presents itself as a
single volume with more than 2^31 blocks.

This means that either:
(1) there's a problem with your drive array under this condition; or
(2) there's a problem with your SCSI controller under this condition; or
(3) there's a problem with FreeBSD under this condition.

To prove which it is, I think you need to show the actual problematic SCSI
command sent to the drive, and the actual response (if any) which comes
back.

According to your log at
http://lists.freebsd.org/pipermail/freebsd-current/2005-June/051163.html
it says that FreeBSD is objecting to the response from the drive array
(protocol violation in Message In phase)

Perhaps someone here can say what's the best way to enable this level of
debugging? From the 5.4 source tree it looks like you can define CAMDEBUG
when building the kernel, and then use "camcontrol debug" to enable
debugging for a particular target (or "all")

Just a suggestion...

Brian.
Received on Thu Jun 09 2005 - 11:05:00 UTC

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