We have a 2 DC cluster running cassandra 1.2.9. They are in actual physically separate DCs on opposite coasts of the US, not just logical ones. The primary use of this cluster is CL.ONE reads out of a single column family. My expectation was that in such a scenario restarts would have minimal impact in the DC where the restart occurred, and no impact in the remote DC.
We are seeing instead that restarts in one DC have a dramatic impact on performance in the other (let's call them DCs "A" and "B").