Apache Cassandra exposes various kind of internal metrics from client read/write request latencies to ColumnFamily’s Bloom filter false positive ratio through JMX. From version 1.1, Cassandra started using Yammer’s Metrics library to track new client request metrics. Cassandra 1.2 expands use of the library to other metrics that are already available and put them together into
org.apache.cassandra.metricsJMX domain. For backward compatibility, metrics are still available through the same JMX location as before (in fact, nodetool is still using old interface), but those implementations are (almost) replaced by new metrics.
METRICS IN APACHE CASSANDRA 1.2