[Linux-cluster] Persistent naming with UDEV and EMC's Powerpath
Robert Hurst
rhurst at bidmc.harvard.edu
Mon Apr 27 14:03:21 UTC 2009
Don't know if this will help your particular issue, but did you
change /etc/lvm/lvm.conf to only look at PowerPath devices, and not SCSI
disks? I don't use a quorum disk, so I would like to see what the final
solution is, too.
For example, on an HP DL385:
filter = [ "a/cciss/", "a/emcpower/", "r/.*/" ]
This tells LVM to only use PVs on the internal Compaq SCSI RAID
controller and under PowerPath control. If you do not do specify this,
and if a path goes down, you are at risk of losing the entire VG.
________________________________________________________________________
Robert Hurst, Sr. Caché Administrator
Beth Israel Deaconess Medical Center
1135 Tremont Street, REN-7
Boston, Massachusetts 02120-2140
617-754-8754 ∙ Fax: 617-754-8730 ∙ Cell: 401-787-3154
Any technology distinguishable from magic is insufficiently advanced.
On Mon, 2009-04-27 at 06:17 -0700, Roberto Fratelli wrote:
> 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 ~]#
>
>
>
>
> --
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>
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