Newts is a time series data schema for Apache Cassandra. It enables horizontal scaling for your time series storage and is an alternative to JRobin and RRDtool.

This section describes how to configure Meridian to use an existing Cassandra cluster, including how to initialize the Newts keyspace using newts init with STCS without production-ready tuning, and verify that time series data is stored and can be accessed

It also provides reference documentation for Newts:

Cassandra documentation

Cassandra cluster design, setup, sizing, tuning, and operation are out of scope for this documentation. To install and set up a Cassandra cluster, please follow the Cassandra installation instructions. For further information, see Cassandra Getting Started Guide.

To avoid unwanted updates, disable the Cassandra repository on DNF/YUM-based distributions or use apt-mark hold cassandra on APT based distributions.
For simplicity we use the ${OPENNMS_HOME}/bin/newts init command which initializes a Newts keyspace for you and the defaults are not optimal tuned for a production-ready environment. To build a production environment please consult Sizing Cassandra for Newts and planning anti-patterns in Cassandra.

Before you begin

Make sure you have the following:

  • A running instance of Meridian running on Linux

  • Working data collection and response time metrics from collectd and pollerd

  • Cassandra cluster with access to the Cassandra client port 9042/tcp

Note that you must make configurations in the etc directory relative to the Meridian Core home directory. Depending on your operating system, the home directory is /usr/share/opennms for Debian/Ubuntu or /opt/opennms for CentOS/RHEL.