From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: different LUN numbers under the same dm device Date: Fri, 08 Jun 2012 08:29:21 +0200 Message-ID: <4FD19BC1.5020702@suse.de> References: <8DCD6D08-35CE-48CC-AC54-7436265C32CB@purestorage.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <8DCD6D08-35CE-48CC-AC54-7436265C32CB@purestorage.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Brian Bunker Cc: dm-devel@redhat.com List-Id: dm-devel.ids On 06/06/2012 09:27 PM, Brian Bunker wrote: > Our company produces a multiple port Fibre Channel storage array. We are = continually plagued > by this problem. We get a dm device which combines paths for different LUN's. We would like > to understand why this is happening. Wouldn't this problem almost certainly lead to a data > corruption? > = Most likely; given that the two LUNs indeed refer to different disks. > Thanks, > Brian > = > 3624a93700a14254d729923840001000b dm-11 PURE,FlashArray > size=3D500G features=3D'0' hwhandler=3D'0' wp=3Drw > `-+- policy=3D'round-robin 0' prio=3D1 status=3Dactive > |- 1:0:0:12 sde 8:64 failed faulty running > |- 0:0:0:12 sdd 8:48 failed faulty running > |- 0:0:0:10 sdar 66:176 active ready running > `- 1:0:0:10 sdba 67:64 active ready running > = > Of the 4 paths to dm-11, we can see two paths are for LUN 10 and the othe= r two are for LUN 12. > We have 24 other dm devices which have only the expected 2 paths. > = Check the output of 'sg_vpd -p di /dev/sd(e|d|ar|ba)'. 'sde' and 'sdd' should be identical (well, the bits for 'Addressed logical unit' should be), as should 'sdar' and 'sdab'. 'sde' and 'sdar', on the other hand, should _not_. Given the above, however, I strongly suspect they are. Looks like your LUN WWID generation code is buggered. But I guess you can always blame Nic Bellinger :-) Greetings to Joern Engel. Cheers, Hannes -- = Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: J. Hawn, J. Guild, F. Imend=F6rffer, HRB 16746 (AG N=FCrnberg)