Amazon RDS support.
RDS is awful. The interface is shitty and buggy, offers graphs that you can't do anything with, the backups cause our system to fail every night, EBS backing has serious spiking problems, you can't access the replicas and it runs a shitty custom fork of MySQL
Thanks for the warning. I was pricing it out but was wary because of weird problems I've experienced with EC2 and inflexibility of ELB.
For what it's worth, I've used Postgres in production systems with great success.
Postgres has had solid replication since 8.4
It was only in Postgres 9.0, released in Septermber 2010, that support for a "hot standby" (e.g. master/slave replication where you can run read-only queries on the slave) was added.
MySQL has supported this since at least version 3.2.3, released in January 2001.
MySQL supports
• Single master to one slave • Single master to multiple slaves • Single master to one slave to one or more slaves • Circular replication (A to B to C and back to A) • Master to master
Postgres supports
• Single master to one slave • Single master to multiple slaves
(lists from http://www.theserverside.com/feature/Comparing-MySQL-and-Pos...)
Built-in two-way (aka master/master) replication.