Metric Collection

Metrics are collected from each node in the cluster so that administrators can use the data to monitor the cluster. In general, the collectd service collects metrics every 10 seconds. The exception is volume metrics which are collected every 10 minutes.

When collectd writes metrics to OpenTSDB, tags are assigned to each metric so that administrators can filter metric data to create dashboards that are specific to their needs.

By default, each metric contains the following tags:
  • fqdn: Displays values for a specified node.
  • clusterid: Displays values for a specific cluster.
  • clustername: As of MEP 3.0, displays values for a specific cluster.
However, many metrics have additional tags that you can use to filter metric data.
collectd stores metrics in OpenTSDB with the following schema:
<> <fqdn:fqdnvalue> <clusterid:clusteridvalue> <clustername:clusternamevalue>[<AdditionalTagA:AdditionalTagAvalue> <AdditionalTagB:AdditionalTagBvalue>...] <metricvalue> <timestamp> 

For more information on using tags and dashboards, see Metric Visualization.