[Linux-cluster] fence_scsi support in multipath env in RHEL5.3

[Moralejo, Alfredo]

I'm using the config provide by Red Hat by default:

       device {
               vendor                  "DGC"
                product                 ".*"
                product_blacklist       "LUN_Z"
                getuid_callout          "/sbin/scsi_id -g -u -s /block/%n"
                prio_callout            "/sbin/mpath_prio_emc /dev/%n"
                features                "1 queue_if_no_path"
                hardware_handler        "1 emc"
                path_grouping_policy    group_by_prio
                failback                immediate
                rr_weight               uniform
                no_path_retry           300
                rr_min_io               1000
                path_checker            emc_clariion
        }

-----Original Message-----
From: linux-cluster-bounces at redhat.com [mailto:linux-cluster-bounces at redhat.com] On Behalf Of Ryan O'Hara
Sent: Thursday, June 11, 2009 12:11 AM
To: linux clustering
Subject: Re: [Linux-cluster] fence_scsi support in multipath env in RHEL5.3

On Wed, Jun 10, 2009 at 11:33:14PM +0200, Moralejo, Alfredo wrote:

> Anyone is successfully using it?

What path checker are you using? I've heard that certain path checkers
cause problems, but I honestly don't know enough about dm-multipath
to understand the reason for this.

I have successfully used it with RDAC.

Ryan

> I'm testing it with a clariion storage frame on RHEL 5.3, and as soon as I enable scsi_reserve, multipath starts failing and a path goes good and bad in a loop and scsi fencing fails sometimes, should I configure in a specific way multipath.conf?:
> 
> Jun 10 23:31:58 rmamseslab07 multipathd: mpath0: remaining active paths: 3
> Jun 10 23:32:00 rmamseslab07 kernel: sd 1:0:0:1: reservation conflict
> Jun 10 23:32:00 rmamseslab07 kernel: sd 1:0:0:1: SCSI error: return code = 0x00000018
> Jun 10 23:32:00 rmamseslab07 kernel: end_request: I/O error, dev sdm, sector 79
> Jun 10 23:32:00 rmamseslab07 kernel: device-mapper: multipath: Failing path 8:192.
> Jun 10 23:32:00 rmamseslab07 multipathd: 8:192: mark as failed
> Jun 10 23:32:00 rmamseslab07 multipathd: mpathquorum: remaining active paths: 3
> Jun 10 23:32:00 rmamseslab07 multipathd: dm-10: add map (uevent)
> Jun 10 23:32:00 rmamseslab07 multipathd: dm-10: devmap already registered
> Jun 10 23:32:00 rmamseslab07 multipathd: sdm: emc_clariion_checker: Path healthy
> Jun 10 23:32:00 rmamseslab07 multipathd: 8:192: reinstated
> Jun 10 23:32:00 rmamseslab07 multipathd: mpathquorum: remaining active paths: 4
> Jun 10 23:32:00 rmamseslab07 multipathd: dm-10: add map (uevent)
> Jun 10 23:32:00 rmamseslab07 multipathd: dm-10: devmap already registered
> Jun 10 23:32:02 rmamseslab07 multipathd: sdl: emc_clariion_checker: Path healthy
> Jun 10 23:32:02 rmamseslab07 multipathd: 8:176: reinstated
> Jun 10 23:32:02 rmamseslab07 multipathd: mpath0: remaining active paths: 4
> Jun 10 23:32:02 rmamseslab07 multipathd: dm-9: add map (uevent)
> Jun 10 23:32:02 rmamseslab07 multipathd: dm-9: devmap already registered
> Jun 10 23:32:03 rmamseslab07 kernel: sd 1:0:0:0: reservation conflict
> Jun 10 23:32:03 rmamseslab07 kernel: sd 1:0:0:0: SCSI error: return code = 0x00000018
> Jun 10 23:32:03 rmamseslab07 kernel: end_request: I/O error, dev sdl, sector 25256
> Jun 10 23:32:03 rmamseslab07 kernel: device-mapper: multipath: Failing path 8:176.
> Jun 10 23:32:03 rmamseslab07 multipathd: dm-9: add map (uevent)
> Jun 10 23:32:03 rmamseslab07 multipathd: dm-9: devmap already registered
> Jun 10 23:32:03 rmamseslab07 multipathd: 8:176: mark as failed
> Jun 10 23:32:03 rmamseslab07 multipathd: mpath0: remaining active paths: 3
> 
> 
> 
> -----Original Message-----
> From: linux-cluster-bounces at redhat.com [mailto:linux-cluster-bounces at redhat.com] On Behalf Of Ryan O'Hara
> Sent: Wednesday, June 10, 2009 9:18 PM
> To: linux clustering
> Subject: Re: [Linux-cluster] fence_scsi support in multipath env in RHEL5.3
> 
> On Wed, Jun 10, 2009 at 02:11:21PM +0530, Rajeev P wrote:
> >  I wanted to know if fence_scsi is supported in a multipath environment for
> > RHEL5.3 release.
> 
> Yes, it is supported.
> 
> > In earlier releases of RHEL5 fence_scsi was not supported in a multipath
> > environment for RHEL5.3 release. If I am not wrong, this was because the
> > DM-MPIO driver forwarded the registration/unregistration commands on only on
> > one of the physical paths of a LUN.  Ideally it should have passed the
> > commands on all physical paths.
> > 
> > For RHEL5.3, is this issue resolved so that I can fence_scsi in multipath
> > environment.
> > 
> > Thanks in advance.
> > 
> > Rajeev
> 
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