#Cassandra

Cassandra

Cassandra is an open source distributed database management system. We use the Jolokia agent to monitor Cassandra’s performance as Cassandra exposes its metrics via JMX. Jolokia connects to a given mbean server and then exposes the server via a REST-like interface, acting as a bridge between JMX and HTTP/JSON. Configuration Download the Jolokia JVM JAR file. Move the downloaded file to the /opt/netuitive-agent/ directory. Add the following line to the very end of the cassandra-env.

Cassandra Metrics

Due to the sheer volume of Cassandra metrics, the individual metrics won’t be documented here. Instead, here are some general properties of the groups of metrics: All Metrics Share the Following Properties: Type: GAUGE Statistic: average Min: 0 Sparse Data Strategy: None BASE: Yes CORR: No UTIL: No Ending in Latency.OneMinuteRate: Unit: ms (milliseconds) Non-latency OneMinuteRate Metrics: Unit = ops (operations per second) Contains HeapSize, DataSize, DiskSpace, Memory, or RowSize: Unit: bytes Ending with HitRate or Ratio: Unit: percentunit (i.

Cassandra Policies

Policy name Duration Conditions Category Description Depressed Key Cache Hit Rate 30 min cassandra.Cache.KeyCache.HitRate has an lower baseline deviation + a static threshold ≤ 0.85 WARNING The hit rate for the key cache is lower than expected and is less than 85%. This condition has been persisting for at least the past 30 minutes. Elevated Node Read Latency 30 min cassandra.Keyspace.ReadLatency.OneMinuteRate has an upper baseline deviation WARNING The overall keyspace read latency on this Cassandra node has been higher than expected for at least 30 minutes.