Configuration

Enabling Time Series Integration Layer

Meridian can be configured to use the Time Series Integration Layer by setting the following property in ${OPENNMS_HOME}/etc/opennms.properties:

org.opennms.timeseries.strategy=integration

After activating the Time Series Integration Layer, you need to start an actual implementation. Do this via Karaf. Here is an example of how to activate the in memory time series plugin:

clone & build:
git clone git@github.com:opennms-forge/timeseries-integration-inmemory.git
mvn install

in Karaf shell:
bundle:install -s mvn:org.opennms.plugins.timeseries.inmemory/timeseries-inmemory-plugin/1.0.0-SNAPSHOT

For specific instructions, check your plugin description.

We also highly recommend that you reference resources stored in the Time Series Integration Layer by their foreign source and foreign ID, as opposed to their database ID. To this end, set the following property in the same file:

org.opennms.rrd.storeByForeignSource=true

With these set, Meridian will begin persisting metrics using the Time Series Integration Layer when restarted.

Additional configuration options are presented in the next section.

Configuration Reference

The following properties, found in ${OPENNMS_HOME}/etc/opennms.properties, can be used to configure and tune the Time Series Integration Layer.

General

Name Default Description

org.opennms.timeseries.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.timeseries.config.writer_threads

16

Number of threads used to pull samples from the ring buffer and insert them into the Time Series Database.

org.opennms.timeseries.query.minimum_step

300000

Minimum step size in milliseconds. Used to prevent large queries.

org.opennms.timeseries.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.timeseries.query.heartbeat

450000

Duration in milliseconds. Used when no heartbeat is specified. Should generally be 1.5x your largest collection interval.

org.opennms.timeseries.query.parallelism

Number of cores

Maximum number of threads that can be used to compute aggregates. Defaults to the number of available cores.

cache.timeseriesPersisterMetaTagCache.expireAfterRead

300

Expiry time in seconds for MetaTagCache.

cache.timeseriesPersisterMetaTagCache.maximumSize

8192

Maximum size for MetaTagCache.

cache.timeseriesPersisterMetaTagCache.recordStats

true

Should cache statistics be exposed via JMX for MetaTagCache?

cache.timeseriesSearcherCache.expireAfterRead

300

Expiry time in seconds for TimeseriesSearcherCache.

cache.timeseriesSearcherCache.maximumSize

8192

Maximum size for TimeseriesSearcherCache.

cache.timeseriesSearcherCache.recordStats

true

Should cache statistics be exposed via JMX for TimeseriesSearcherCache?

cache.timeseriesMetaDataCache.expireAfterRead

300

Expiry time in seconds for TimeseriesMetaDataCache.

cache.timeseriesMetaDataCache.maximumSize

8192

Maximum size for TimeseriesMetaDataCache.

cache.timeseriesMetaDataCache.recordStats

true

Should cache statistics be exposed via JMX for TimeseriesMetaDataCache?

Recommendations

Caches have been introduced to improve performance. You might need to tune the cache settings to suit your needs. See parameters above.

Name Description

TimeseriesMetaDataCache

Caches metadata that uses Meridian internally.

TimeseriesSearcherCache

Caches metrics by tag to improve the resource lookup.

TimeseriesPersisterMetaTagCache

Caches all additionally configured and resolved meta-tag values by resource.

The samples gathered by the collectors are temporarily stored in a ring buffer before they are persisted to the Time Series Integration Layer. The value of the ring_buffer_size should be increased if you expect large peaks of collectors returning at once or latency in persisting these. However, note that the memory used by the ring buffer is reserved, and larger values may require an increased heap size.

Expose additional meta tags

Metrics that are stored via the time series plugin contain the minimal set of tags for Meridian to work. This might not be sufficient if the data is used outside of Meridian as well. Configure additional meta tags via ${OPENNMS_HOME}/etc/opennms.properties.

The configuration of the tags has the following form: prefix.tagKey=${\query expression}

  • The prefix is: org.opennms.timeseries.tin.metatags.tag

  • The tagKey can by an arbitrary string as long as it doesn’t break the java property file syntax.

  • The query expression lets you query the value. Supports use of the Meta-Data-DSL

Examples: org.opennms.timeseries.tin.metatags.tag.nodelabel=${node:label} org.opennms.timeseries.tin.metatags.tag.sysObjectID=${node:sys-object-id}

Expose categories by setting org.opennms.timeseries.tin.metatags.exposeCategories to true.

Example: org.opennms.timeseries.tin.metatags.exposeCategories=true will lead to: Tag("cat_myFirstCategory", "myFirstCategory") Tag("cat_mySecondCategory", "mySecondCategory")