[Linux-cluster] DLM or GULM?

[Kevin Anderson]

On Sun, 2006-01-15 at 20:59 +0100, Troels Arvin wrote:
> Hello,
> 
> I'm setting up two RHEL 4 servers (HP DL380G4) in a fail-over solution,
> using Red Hat Cluster Suite. The two servers are both connected to a HP
> MSA 500G2 RAID storage system (which has two SCSI connectors).
> 
> I don't have plans about using GFS at the moment: Only one server will be
> mounting the shared storage system at a time. I plan on using iLO fencing.
> 
> The Red Hat Cluster Suite documentation mentions that either DLM or GULM
> should be used for lock management. However, the documentation doesn't
> cover on what basis the choice should be made.
> 
> When would DLM be the best choice, and when would GULM be the lock manager
> to go for?

DLM is the best choice.  GuLM requires at least 3 nodes in order to
maintain proper quorum in the cluster.  DLM has a special 2 node
configuration setup that removes this requirement.

Kevin