[nirvana]

Do you have data for the difference in latency &/or bandwidth between servers on the same rack at Hetzner vs. on different racks?

I was assuming that having the servers in different racks would be an advantage, mainly because the reason I have multiple servers is for data redundancy (I'm using Riak and data is replicated across the cluster.) However, in Riak the servers do talk to each other a fair bit.

The latency and bandwidth between a given server and a web browser out in the world shouldn't vary much from rack to rack, I'm assuming.

[mike_esspe]

Sometimes i had a 5-10% ping loss between servers in the same Hetzner datacenter, so not being on the same rack can be a problem. Especially if you are using nginx -> backend. Then every request is a TCP connect to the backend server, and when SYN packet is lost, you will have a 3 seconds timeout (at least on FreeBSD TCP stack).