[Linux-cluster] High Availability options

[Lon Hohberger]

On Thu, 2006-07-13 at 12:14 -0500, Stephen Kirkpatrick wrote:

> Thanks for the reply.  I wondered if it was possible to have HA for 
> stateful applications.  At least
> I know my options better now.  I can tolerate brief downtime, like the 
> time it would take a failover
> node to take over, although no downtime would have been preferred.
> 
> Any suggestions on HA solutions for a non-SAN deployment?

You don't need a SAN if you don't intend to share data.  

If you intend to share data but do not want a SAN, you'll need to set up
DRBD or CLVM+Cluster Mirroring+GNBD (Note: cluster mirroring is still in
a bit of development).  The main advantage to the latter approach is
simultaneous read/write access from both machines in the cluster.  The
advantage to DRBD is that it is easier to set up.

Alternatively, you could use NFS mounts from a good NAS (a NetApp filer,
as an example) as your source for shared dat.

You can use linux-cluster or Linux-HA to do failover with or without a
SAN; the choice is up to you.  Linux-HA supports DRBD out of the box,
but CLVM will still need parts of linux-cluster running in order to
operate.

If you want support, you can use Red Hat Cluster Suite (which is
effectively linux-cluster w/ support).

Good luck!

-- Lon