[Linux-cluster] Persistent naming with UDEV and EMC's Powerpath
berthiaume_wayne at emc.com
berthiaume_wayne at emc.com
Mon Apr 27 14:43:02 UTC 2009
Hi Roberto.
You can use the emcpadm() command to rename the device on each
node so they are all the same. The syntax is "emcpadm rename[pseudo] -s
src pseudodevice -t tgt pseudodevice". For example, if on node A the
device is emcpowerg and you wish it to be be emcpowerq you would issue:
# emcpadm rename -s emcpowerg -t emcpowerq
For each node run the "powermt display dev=all" and review the
Logical device ID that is displayed for each LUN on each node. Find your
quorom disk on each - for example, Logical device
ID=6006016018C80800B5069570B8A9D911
# powermt display dev=emcpowerg
Pseudo name=emcpowerg
CLARiiON ID=WRE00100100415
Logical device ID=6006016018C80800B5069570B8A9D911
state=alive; policy=CLAROpt; priority=0; queued-IOs=0
Owner: default=SP A, current=SP A
======================================================================
------------ Host ----------- - Stor - -- I/O Path - -- Stats ---
### HW Path I/O Paths Interf. Mode State Q-IOs Errors
======================================================================
3 lpfc sdaa SP A0 active alive 0 0
2 lpfc sdj SP A1 active alive 0 0
Then rename it....
# emcpadm rename -s emcpowerg -t emcpowerq
...and your in business.
Regards,
Wayne.
-----Original Message-----
From: linux-cluster-bounces at redhat.com
[mailto:linux-cluster-bounces at redhat.com] On Behalf Of Roberto Fratelli
Sent: Monday, April 27, 2009 9:18 AM
To: linux-cluster at redhat.com
Subject: [Linux-cluster] Persistent naming with UDEV and EMC's Powerpath
Hello everyone !
I'm trying to set up a quorum disk in a 2-node redhat cluster (RHEL
4.7). Both nodes are attached to a SAN Clariion over qlogic HBA's and
i'm using EMC's powerpath.
The problem i'm facing is that the disks's device names are different
across the nodes. For example, the lun i elected to be my quorum disk is
called '/dev/emcpowerf' at node-a and '/dev/emcpowerd' at node-b, so i
can't use the device name (/dev/emcpowerXX) in my cluster.conf file. In
a attempt to overcome this i've tried to use the disk label instead :
<quorumd label="97196ef0-da2f-4b79-a5c5-999dce70d677" interval="2"
tko="10" votes="1"/>
But did not work also, because this way it finds '/dev/sdXX' before
'/dev/emcpowerXX':
root at node-a:~ # cman_tool nodes
Node Votes Exp Sts Name
0 1 0 M /dev/sdf1
1 1 2 M node-a
2 1 2 M node-b
root at node-a:~ #
Since this '/dev/sdf' is just one of the paths i have under powerpath
(it has 4 paths per HBA, 8 paths per lun total) i can't keep it this way
because in a event of lun trespass (clariion does it very often) i would
loose quorum. My understanding is that i need some kind of "persistent
binding" so i can use Powerpath's pseudo-device '/dev/emcpowerXX', so i
tried to create a UDEV rule like this:
[root at node-a RSM]# cat 75-quorum.rules
KERNEL=="emcpower[a-z]1,
SYSFS{label}=="97196ef0-da2f-4b79-a5c5-999dce70d677",
SYMLINK+="discodequorum%n"
[root at node-a RSM]#
Which did not worked, i think because UDEV starts way before powerpath.
Does anyone here faced this problem before ? how can i keep the device
names persistent across the nodes (at least for the quorum disk) ?
Below some more info on my quorum's disk:
root at node-a:~ # mkqdisk -L
mkqdisk v0.5.2
/dev/sdf1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/sdo1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/sdx1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/sdag1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/sdap1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/sday1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/sdbh1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/sdbq1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/emcpowerf1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
root at node-a:~ #
[root at node-b ~]# mkqdisk -L
mkqdisk v0.5.2
/dev/sdf1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/sdo1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/sdx1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/sdag1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/sdap1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/sday1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/sdbh1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/sdbq1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
/dev/emcpowerd1:
Magic: eb7a62c2
Label: 97196ef0-da2f-4b79-a5c5-999dce70d677
Created: Mon Dec 24 11:47:11 2007
Host: node-a
Kernel Sector Size: 512
[root at node-b ~]#
--
Linux-cluster mailing list
Linux-cluster at redhat.com
https://www.redhat.com/mailman/listinfo/linux-cluster
More information about the Linux-cluster
mailing list