I've set up a Postgres database on a server with 2 CPU cores, 4GB of RAM and an SSD volume (on top of RAID 10 of course). This is our (sort-of) "beefy" production database server (I can easily add more RAM, etc. when the time comes).
Now it's time to set up a backup Postgres server (not used for reads or anything else, just strictly a replication/backup). I don't want to have to fork out another $150/mo for the same exact setup for my backup server, and I know that a lot of the server resources used for a production database have to do with complicated queries, sequential scans, etc., so my thinking was that I could get away with a 512MB server with about 1/6 the I/O performance, and 1 CPU core.
Is that thinking correct, or does a replication/backup Postgres server typically need nearly the same specs as a production Postgres server?
Note: I'm using Postgres 9.2.4 with streaming (non-synchronous) replication on an Ubuntu 12.04.2 server.