[Linux-cluster] RHEL 4.8 QDisk DM-Multipath Issue

[Pak, Mesut]

Here is the latest:

With emulex hba, in /etc/modprobe.conf: lpfc_nodev_tmo is 30 secs.

Changed following:

/etc/multipath.conf: "polling_interval 10", "no_path_retry 4" (x=40)

cluster.conf: qdisk "interval 13" & "tko 4" (Qdisk failover = x * 1.3 = 52 = 13 *4)

cman "deadnode_timeout 108" ( x * 2.7) and "quorum_dev_poll 75".

With these values, we first hit lpfc_nodev_tmo in 30 secs.
After that multipathd does failovers.
It appears to work.
No longer getting kicked out of cluster while pulling fibres.

But mkqdisk -L output would still show non-multipath disk names in its output.

Thanks for the input.


________________________________
From: linux-cluster-bounces at redhat.com [mailto:linux-cluster-bounces at redhat.com] On Behalf Of umesh susvirkar
Sent: Thursday, August 12, 2010 1:28 AM
To: linux clustering
Subject: Re: [Linux-cluster] RHEL 4.8 QDisk DM-Multipath Issue

i have not use multipath on rhel 4.8

but check if is due to max length for device name as in following bugzilla  ( following is for rhel 5.0 )

https://bugzilla.redhat.com/show_bug.cgi?id=294351#c2

try to assign name which is < 16 in /etc/multipath.conf & check if its working.
try giving /dev/mapper/qd in your /etc/cluster.conf

<https://bugzilla.redhat.com/show_bug.cgi?id=294351#c2>
On Thu, Aug 12, 2010 at 4:24 AM, Paul M. Dyer <pmdyer at ctgcentral2.com<mailto:pmdyer at ctgcentral2.com>> wrote:
I use multipath on RHEL 5.5 with RHCS clusters.   The "multipath -l" should show you if your paths are available.

Paul

----- Original Message -----
From: "Mesut Pak" <mesut.pak at nscorp.com<mailto:mesut.pak at nscorp.com>>
To: "linux-cluster at redhat.com<mailto:linux-cluster at redhat.com>" <linux-cluster at redhat.com<mailto:linux-cluster at redhat.com>>
Sent: Tuesday, August 3, 2010 1:16:35 PM
Subject: [Linux-cluster] RHEL 4.8 QDisk DM-Multipath Issue

MP Stationery
I am having a back and forth with RH support on this.
Problem is my fibre attached qdisk is dm-multipathed yet when I issue
"mkqdisk -L" I don't see the /dev/mapper/mpath... but LUNs seen from
individual fibre paths.
In addition when I unplug cable (path B) for /dev/sdh1 (same as
/dev/dm-13), that node gets fenced out.

# mkqdisk -L
mkqdisk v0.5.2
/dev/sdd1:
Magic: eb7a62c2
Label: san_qdisk
Created: Mon Aug 2 13:19:09 2010
Host: host1
Kernel Sector Size: 512
Recorded Sector Size: 512

/dev/sdh1:
Magic: eb7a62c2
Label: san_qdisk
Created: Mon Aug 2 13:19:09 2010
Host: host1
Kernel Sector Size: 512
Recorded Sector Size: 512

/dev/dm-13:
Magic: eb7a62c2
Label: san_qdisk
Created: Mon Aug 2 13:19:09 2010
Host: host1
Kernel Sector Size: 512
Recorded Sector Size: 512

Has anybody got dm-multipath working for qdisk on RHEL 4.8 cluster?
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