This article is pretty thin. We are currently building out a clustered application on corosync/pacemaker with postgres synchronous replication and tomcat, and I have mixed feelings about Linux HA so far. It isn't too bad to get something basic set up (cluster with virtual IP for instance), but when things don't work it can be difficult to figure out why. If you are looking for a distributed filesytem GFS2 in this stack isn't bad. However, it seems like there are a lot of differences between package versions, and the interactions between versions of heartbeat, corosync, pacemaker, crm, pcs, your resource definition ocf files, the stonith resources, cluster-glue, along with the linux packages makes problems hard to track down and much of the web info you do find out of date. I've often had to resort to irc or the mailing list to try and figure things out, and even then sometimes it seems like nobody knows. The whole thing feels a little bit shaky at first, but it is possible to build a solid cluster on top of it with enough effort.