Hi,
we have a cluster of 11 nodes running Cassandra 2.2.9 where we regularly get READ messages dropped: > READ messages were dropped in last 5000 ms: 974 for internal timeout > and 0 for cross node timeout Looking at the logs, some are logged at the same time as Old Gen GCs. These GCs all take around 4 to 6s to run. To me, it's "normal" that these could cause reads to be dropped.However, we also have reads dropped without Old Gen GCs occurring, only Young Gen. I'm wondering if anyone has a good way of determining what the _root_ cause could be. Up until now, the only way we managed to decrease load on our cluster was by guessing some stuff, trying it out and being lucky, essentially. I'd love a way to make sure what the problem is before tackling it. Doing schema changes is not a problem, but changing stuff blindly is not super efficient :) What I do see in the logs, is that these happen almost exclusively when we do a lot of SELECT. The time logged almost always correspond to times where our schedules SELECTs are happening. That narrows the scope a little, but still. Anyway, I'd appreciate any information about troubleshooting this scenario.Thanks.
