Scalar i40 tapechanger LUN appearing as a second tape drive

[Kenneth D. Merry]

On Wed, May 16, 2018 at 10:48:54 +0200, Dirk-Willem van Gulik wrote:
> 
> > On 15 May 2018, at 22:19, Kenneth D. Merry <ken at FreeBSD.ORG> wrote:
> > 
> > On Sun, May 13, 2018 at 20:00:21 +0200, Dirk-Willem van Gulik wrote:
> >> While having to re-surrect a Quantum Scalar i40 LTO5 unit - on a stock  11.1-RELEASE-p6  wired up with a external SAS cable to a HP Smart Array P222 I am seeing:
> >> 
> >> 	camcontrol devlist 
> >> 	...
> >> 	<HP Ultrium 5-SCSI Z6KZ>           at scbus3 target 4 lun 0 (sa0,pass1)
> >> 	<HP Ultrium 5-SCSI Z6KZ>           at scbus3 target 4 lun 1 (pass2,sa1)
> >> 	....	
> >> 
> >> rather than the tape drive on LUN 0 and the tape changer on LUN 1 (the control path is to this drive - the serial number matches - and in like with the web interface details). 
> >> 
> >> dmesg shows:
> >> 
> >> 	...
> >> 	sa0 at ciss1 bus 32 scbus3 target 4 lun 0 
> >> 	sa0: Serial Number C38CEFF000
> >> 	...
> >> 	sa1 at ciss1 bus 32 scbus3 target 4 lun 1
> >> 	...
> >> 	sa1: Serial Number C38CEFF000
> >> 
> >> The second drive (Serial C38CEFF004) is not wired up. Or if it is - it nicely shows up at the right (different) target and LUN0, without a second LUN.
> >> 
> >> Does this ring a bell with any one ? The kernel has ch(4), sa(4) and pass(4) compiled in statically (and is known to work with other tape changers/libraries).
> >> 
> > 
> > When you hooked other tape changers up, was it to the same machine, and
> > also to the ciss(4) controller?  Was the configuration the same?
> 
> Yes (but *).
> 
> > It looks like the array controller is moving things around.
> > 
> > I would suggest taking a look at configuration options for the controller
> > to see if you can adjust the way it does passthrough.
> 
> The control-path can indeed be set. It is set correctly (we also tried the 3 other permutations possible).
> 

Ok.  Perhaps the RAID controller firmware was updated since the last time
you did this, and it doesn't work as well as it used to work.

> > Or, if you can find one, put a standard SAS controller in there (as opposed
> > to a RAID controller) and hook that up to the tape library.
> 
> Ok. good advice. Will do exactly that.

The best controllers to use are LSI (now Broadcom) 6Gb or 12Gb SAS
controllers.  They have TLR support, which helps insure data integrity with
tape drives.

> > It is unlikely that FreeBSD is causing this behavior.  It really looks like
> > the RAID controller is giving you multiple copies of the same tape drive.
> 
> Thanks. The odd thing is that this very configuration/card/etc has worked around 8.x.
> 

Yeah, it is odd.  Perhaps the ciss driver got updated, or perhaps the RAID
firmware got updated.  In any case, a standard SAS controller should
eliminate the problem.  (Spectra Logic ships LSI controllers for use with
tape libraries, so I know that works.)

> 
> *: the Quantum Scalar i40???s have the annoying habit to self-check their firmware and prime themselves for auto update with a fairly easy to miss cancel prompt on the screen. So we are not a 100% it was not updated during the re-racking by someone going through the re-calibration mindlessly.

Ahh, interesting.

Ken
-- 
Kenneth Merry
ken at FreeBSD.ORG