> Could this be related as well to > https://issues.apache.org/jira/browse/CASSANDRA-2463?
My gut feel: Maybe, if the slowness/timeouts reported by the OP are intermixed with periods of activity to indicate compacting full gc. OP: Check if cassandra is going into 100% (not less, not more) CPU usage during periods of timeouts. If the huge allocations fail due to fragmentation and fallback to Full GC that might be an expected result. Else -XX:+PrintGC -XX:+PrintGCDetails -XX:+PrintGCTimeStamps. -- / Peter Schuller
