[Linux-cluster] SCSI PR fencing

[Ryan O'Hara]

On Fri, Feb 06, 2009 at 12:10:34AM +0530, Rajeev P wrote:
> Hi,
> 
> Consider a two node RHEL5 cluster that is configured with SCSI PR fencing
> but without a qdisk. In the event of network split, nodes will attempt to
> fence the other one. One of the node's (node that lost the race) key will be
> successfully removed from the disk and key of the node that won race will be
> present on the disk.

This is correct.

> The question I have is that, in the event of a network split, is there a
> possibility (even remote) for both the nodes to "successfully" fence each
> other? That is key of both the nodes are successfully removed from the
> disk.

It should not be possible for both nodes to remove the other node's
key. The first "unregister" command to hit the scsi device will
determine the winner. The reason this works is due to the fact that
a node must be registered with a device in order to remove keys.

Ryan