http://wiki.apache.org/cassandra/FAQ#dropped_messages
As to what's causing them - look in the logs and it will do the equivalent of a
nodetool tpstats right after the dropped messages messages. That should give
you a clue as to why there are dropped messages - which thread pools are backed
up
How can I tell what's causing dropped messages?
Is it just too much activity? I'm not getting any other, more specific
messages, just these:
WARN [ScheduledTasks:1] 2011-08-15 11:33:26,136 MessagingService.java (line
504) Dropped 1534 MUTATION messages in the last 5000ms
WARN [ScheduledTasks:1] 2
