Disabling thrift results in unclosed thrift sockets being left around.
Steps to reproduce and observe:
1. Have a handful of clients connect via thrift.
2. Disable thrift.
3. Enable thrift, have the clients reconnect.
4. Observe netstat or lsof, and you'll find a lot of thrift sockets in CLOSE_WAIT state, and they'll never go away.
- Also verifiable from org.apache.cassandra.metrics:type=Client,name=connectedThriftClients MBean.
What's extra fun about this is the leaked sockets still count towards your maximum RPC thread count. As a result, toggling thrift enough times will result in an rpc_max_threads number of CLOSED_WAIT sockets, with no new clients able to connect.
This was reproduced with HSHA. I haven't tried it in sync yet.