OpsCenter collects system and column family metrics data for each node in your cluster. OpsCenter creates its own keyspace within a cluster for storing collected metrics. Metrics data is collected at regular intervals and stored within your cluster in a keyspace called OpsCenter. The column families containing metric data continue to grow. You can configure how long you want to keep historical metrics. Data expires after configurable time periods.
The following table provides guidance for estimating the amount of metrics data generated:
|Number of days||Number of column families monitored||MB per node|
The default upper limit of data collected is 365 days.
To help control consumption of disk space, OpsCenter provides two ways to limit the growth of OpsCenter performance data:
By default, OpsCenter does not collect performance data for its own keyspace or the Cassandra system keyspace. You can manually add any other keyspaces or column families that you do not want to monitor in the [cassandra_metrics] section of the configuration file.
For example, to prevent data collection for the keyspace test as well as the column family Keyspace1.Standard1, uncomment and edit the following values in the OpsCenter cluster configuration file (<cluster_specific>.conf):
[cassandra_metrics] ignored_keyspaces = system, OpsCenter, test ignored_column_families = Keyspace1.Standard1
Column families are specified in the format:
Performance data stored in OpsCenter expires after configurable time periods. The default values are designed to provide efficient compaction and eventual deletion of the data, with faster expiration times for the more granular, larger-volume data rollups.
To change expiration time period:
Uncomment and edit the time-to-live (ttl) values in opscenterd.conf.
In the following example, the one-minute and five-minute rollups are set to expire twice as fast as the defaults, and two-hour rollups are set to be kept indefinitely (expiration is disabled):
1min_ttl = 302400 5min_ttl = 1209600 2hr_ttl = -1
Data collected after restarting OpsCenter expires according to the new setting. The data collected before restarting OpsCenter expires according to the setting in effect when it was collected.