I just asked this exact same question but after maybe after reading a bit more doc than you did. You may want to read this thread: http://grokbase.com/t/cassandra/user/134j85av4x/ec2snitch-to-ec2multiregionsnitch

You also may want to read some doc. Datastax explain things quite well and update the doc regularly.

Hope this will help.

2013/4/25 Daning Wang <daning@netseer.com>
Hi All,

We have 8 nodes cluster(replication factor is 3), about 50G data on each node. we need to change the cluster to multi-center environment(to EC2). the data need to have one replica on ec2.

Here is the plan,

- Change cluster config to mult-center.
- Add 2 or 3 nodes in another center, which is ec2.
- Change the replication factor to make data synced to other center.

We have not done the test yet, is this doable? the main concern is that since connection to ec2 is slow, it will take longer time to streaming data(should be more than 100G) at the beginning.

Anybody has done this before, please share some light,

Thanks in advance,