Does anyone have any experience (success or horror stories, either way) with running a simple active-passive Zimbra cluster using keepalived as the cluster mechanism?

I know that there are well documented and supported means of running Zimbra in a clustered environment, but I'm wondering if, for the very simple single server install case, anyone has tried to avoid the complexity of using Red Hat's Cluster Suite.

I will be backing this with a SAN.

Anyone have any experience or other input?