Query about cluster lock disk.

[Stefan Saliba]

I have a small query about a cluster lock disk. Assume you have 2 sc10 enclosures mirroring each other. Let us say that the device file of a disk in one SC10 is c0t5d0 and that the equivalent mirror on the other SC10 is C1t5d0.

In the cluster conf file which device file do I specify. Should I specify the 2 device files or just one leaving the mirror copy out ?

[Duncan Edmonstone]

You need to just specify one - cluster lock disks have no concept of mirroring.

HTH

Duncan

[melvyn burnard]

The cluster binary will look at the Physical Device only, and the Cluster Lock info gets written in the Bad Block Allocation area on the physical disk.
As mirroring does NOT mirror the BBA, you cannot mirror the Cluster Lock Info.
Specify one device only.

[Stefan Saliba]

So when that disks fails and the system reverts to the mirror there is no chance of accessing the lock disk ?

[Vijeesh CTK]

hi

Specify one device only . i'll prefer the primary (link) device. ( vgdisplay )

CTK

[Duncan Edmonstone]

Yes, if the cluster lock disk fails, then MCSG will start reporting this in your syslog.

The cluster lock disk is not needed during normal cluster operation, only during cluster reformation when quorum cannot be established. So it would take multiple points of failure for this to effect your system.

HTH

Duncan

[melvyn burnard]

If the CL disk fails, then if you have done a vgcfgbackup of the PV/VG AFTER the CL info was written to it, then a vgcfgrestore will restore the CL info.
If not, you will have to halt the cluster and reapply the SG binary with the CL VG activated on a node.

Remember, you only NEED the cl disk in the event that there is a failure scenario where you have EXACTLY 50% of the cluster nodes remaining at a cluster reformation.

[Stefan Saliba]

ok, thanks for the help