I have a site that has a postgres database server. 24 hour availability is pretty critical to them, so I want to turn it into a redundant cluster for high availability. I currently have a streaming backup server, but we want to be able to make either server capable of accepting writes in the case one fails. The problem with streaming backup is that we can promote the backup when the master fails, but when the master comes backup you basically have to rebuild the entire database and reconfigure postgres on it to either make it the master or make it into a new streaming backup. We want something that’s much more dynamic, so writes can go either direction in the event of one or the failing, and so that things will automatically resync when a failed server in the cluster comes back online.
Given these goals – pgpool-II, pgcluster, pgbouncer? Some other tool that I haven’t even considered?