As described previously, Porcupine automatically reconfigures whenever nodes fail or restart. Both figures show the same behavior.
Nodes fail and throughput drops dramatically as two things occur.
First, the system goes through its reconfiguration protocol, increasing its load. Next, during the reconfiguration, SMTP and POP sessions that involve the failed node are aborted. After ten seconds, the system determines the new membership, and throughput increases as the remaining nodes take over for the failed ones. The failed nodes recover 300 seconds later and rejoin the cluster, at which time throughput starts to rise. With replication, throughput rises slowly as the failed nodes reconcile while concurrently serving new requests.