Compaction metrics 

Monitoring compaction performance is an important aspect of knowing when to add capacity to your cluster.

Monitoring compaction performance is an important aspect of knowing when to add capacity to your cluster. The following attributes are exposed through CompactionManagerMBean:
Compaction Metrics
Attribute Description
BytesCompacted Total number of bytes compacted since server [re]start
CompletedTasks Number of completed compactions since server [re]start
PendingTasks Estimated number of compactions remaining to perform
TotalCompactionsCompleted Total number of compactions since server [re]start