[Linux-cluster] newbie mirrored LVM/GFS query

[James Fidell]

I'm running a couple of CentOS4.5 boxes with all current updates
configured as a cluster.  Both have access to the same three
iscsi-connected disks on which I've created a mirrored LVM volume.
I've created a GFS filesystem on the LVM volume and can mount it
and read/write from both machines in the cluster.  So far, so good.

Now I want to test what happens when different parts of the system
fail.  First I thought I'd try disconnecting one of the iscsi disks
that form the data component of the LVM mirror, leaving the other
data disk and log active.  I expected LVM to fail the disk and run
in degraded linear mode until I restored the disconnected disk.

What actually happens is that all access to the LVM volume hangs.
The iscsi layer on the cluster servers logs that the connection has
dropped, but that's it.

Am I missing something important here, or is this just expecting too
much?

James