Configuration Reference Use the following properties, found in ${OPENNMS_HOME}/etc/opennms.properties, to configure and tune Newts. General Name Default Description org.opennms.newts.config.keyspace newts Name of the keyspace to use. org.opennms.newts.config.hostname localhost IP address or hostnames of the Cassandra nodes. Separate multiple hosts by a comma. org.opennms.newts.config.port 9042 CQL port used to connect to the Cassandra nodes. org.opennms.newts.config.username cassandra Username to use when connecting to Cassandra via CQL. org.opennms.newts.config.password cassandra Password to use when connecting to Cassandra via CQL. org.opennms.newts.config.ssl false Enable/disable SSL when connecting to Cassandra. org.opennms.newts.config.core-connections-per-host Driver default Core number of connections per host. org.opennms.newts.config.max-connections-per-host Driver default Maximum number of connections per host. org.opennms.newts.config.max-requests-per-connection Driver default Maximum number of requests that can be in-flight on a single connection at the same time. org.opennms.newts.config.read_consistency ONE Consistency level used for read operations. See Configuring data consistency for a list of available options. org.opennms.newts.config.write_consistency ANY Consistency level used for write operations. See Configuring data consistency for a list of available options. org.opennms.newts.config.max_batch_size 16 Maximum number of records to insert in a single transaction. Limited by the size of the Cassandra cluster’s batch_size_fail_threshold_in_kb property. org.opennms.newts.config.ring_buffer_size 8192 Maximum number of records that can be held in the ring buffer. Must be a power of two. org.opennms.newts.config.writer_threads 16 Number of threads used to pull samples from the ring buffer and inserted into Newts. org.opennms.newts.config.ttl 31540000 Number of seconds after which samples will automatically be deleted. Defaults to one year, in seconds. org.opennms.newts.config.resource_shard 604800 Duration in seconds for which samples will be stored at the same key. Defaults to 7 days in seconds. org.opennms.newts.query.minimum_step 300000 Minimum step size in milliseconds. Used to prevent large queries. org.opennms.newts.query.interval_divider 2 If no interval is specified in the query, the step will be divided into this many intervals when aggregating values. org.opennms.newts.query.heartbeat 450000 Duration in milliseconds. Used when no heartbeat is specified. Should generally be 1.5 times your largest collection interval. org.opennms.newts.query.parallelism Number of cores Maximum number of threads that can be used to compute aggregates. Defaults to the number of available cores. org.opennms.newts.config.cache.strategy See below Canonical name of the class used for resource-level caching. See the table below for all of the available options. org.opennms.newts.config.cache.max_entries 8192 Maximum number of records to keep in the cache when using an in-memory caching strategy. org.opennms.newts.nan_on_counter_wrap false Disables the processing of counter wraps, replacing these with NANs instead. org.opennms.newts.config.cache.priming.disable false Disables the cache primer, which preemptively loads the cache with indexed resources on start-up. org.opennms.newts.config.cache.priming.block_ms 120000 Block start-up for this many milliseconds while waiting for the cache to be primed. Set this value to -1 to disable blocking. Set this value to 0 to block indefinitely waiting for all of the records to be read. Available caching strategies include: Name Class Default In-Memory Cache org.opennms.netmgt.newts.support.GuavaSearchableResourceMetadataCache Y Redis-based Cache org.opennms.netmgt.newts.support.RedisResourceMetadataCache N Redis Cache When enabled, the following options can be used to configure the Redis-based cache. Name Default Description org.opennms.newts.config.cache.redis_hostname localhost IP address of hostname of the Redis server. org.opennms.newts.config.cache.redis_port 6379 TCP port used to connect to the Redis server. Recommendations You will likely want to change the values of cache.max_entries and the ring_buffer_size to suit your installation. Horizon caches metadata related to resources to avoid writing redundant records in Cassandra. If you are collecting data from a large number of resources, you should increase the cache.max_entries to reflect the number of resources you are collecting from, with a suitable buffer. The samples the collectors gather are temporarily stored in a ring buffer before they are persisted to Cassandra using Newts. You should increase the value of the ring_buffer_size if you expect large peaks of collectors returning at once or latency in persisting these to Cassandra. However, note that the memory the ring buffer uses is reserved, and larger values may require an increased heap size. Newts uses cache priming to help reduce the number of records that need to be indexed after restarting Horizon. This works by rebuilding the cache using the index data that has already been persisted in Cassandra. If you continue to see large spikes of index-related inserts after rebooting, consider increasing the amount of time spent priming the cache. Newts Cassandra Monitoring