Based on our usage, I think Thrift is the Achilles' heel for Cassandra. Some of Trift problems that we've seen:
* simple port scan can crash Thrift.
* Malform data can crash Thrift.
* inserting data too fast can crash Thrift.
Any of the 3 above cause NoServersAvailable error.
That said, do you guys have road-map for replacing Thrift? Apache Avro perhaps? Are there anyone actually happy with Thrift (besides Facebook)?