Nope but if I pay a few K for a service I expect it to scale to perfomance at least comparable to a very low end device. Why would I use DRBD in a Postgres clus

Nope but if I pay a few K for a service I expect it to scale to perfomance at least comparable to a very low end device. Why would I use DRBD in a Postgres cluster? I am not underestimating anything I am simply pointing out that RDS is overpriced and crappy service. A proper setup & operation of a postgres cluster is manageable task. What you totally can not manage on AWS is the risks of having single tenant that is using 30% of resources or having lengthy multi AZ outages due to bugs in extremely complex control layer etc.