[Pacemaker] Resource-level fencing without stonith?

[Lajos Pajtek]

Hi,

I am building a two-node, active-standby cluster with shared storage. I think I got the basic primitives right, but fencing, implemented using SCSI persistent reservations, gives me some headache.First, I am unable to get stonith:fence_scsi work on RH/CentOS 6. (Using the sg_persist utility I am able to register keys, etc so that's not the problem.) 

This made me think about the fact that conceptually SCSI fencing should be resource-level fencing, not node-level fencing. The other node is not powered down or rebooted so perhaps I shouldn't be using stonith at all. Currently I think about having stonith-enabled="false" and I am writing a master-slave resource agent script to manage the SCSI persistent reservations in case of fail-over. Acting upon failed shared storage link seems to work, but I do not exactly know how to detect split brain. The latter case seems to be the critical one requiring fencing the shared storage. Any hints on how to do this? More generally, are there any guidelines for setting up a cluster with stonith disabled and resource-level fencing?

Thank and regards,
Lajos