> If you want to survive node failures, use an RF above 1. And then make > sure to use an appropriate consistency level.
To elaborate a bit: RF, or replication factor, is the *total* number of copies of any piece of data in the cluster. So with only one copy, the data will not be available when a single node is down. Consistency levels control how many nodes are required to respond to requests before it is considered successful, and this has implications on availability. For example, if you want to survive a single node going down and you use RF=2, you must use ConsistencyLevel.ONE. If you used QUORUM or ALL, any read or write would fail (QUORUM of 2 is 2). Probably a common setup is to use RF=3 because it allows you to survive a node going down, while also allowing you to use QUORUM. But, whether that matters will be up to your use-case. -- / Peter Schuller (@scode, http://worldmodscode.wordpress.com)
