The Index Cache Retention mechanism uses rules to control keeping or deleting index data that is stored in the Index Cache Directory. It works by applying the retention parameters that are set on the MediaAgent Properties > Catalog tab. Deleting cache data is called cleanup. Cleanup happens automatically, as described in How Does Index Cache Cleanup Work?.
The four retention parameters are:
|Index retention time in days||The number of days an index is kept, if it is not deleted sooner by an event-driven cleanup. When an index is older than this, it is aged (deleted) within 24 hours. By default, this parameter is set to 15 days.|
|Index cleanup percent||During an event-driven cleanup, if the percentage of used space remaining after indexes are aged is still greater than this value, additional indexes are removed, on a least-recently-used basis, until the used space percentage for the volume becomes equal to or less than this value.|
|Minimum Free Space (MB)||The total amount of free space that must be available at all times in the index cache. If the amount of free space falls below this value, an event-driven cleanup kicks off and the index cache is taken offline until the cleanup is completed.|
|Free Space Warning (MB)||The amount of free space in megabytes on the index cache volume below which disk space is considered to be low enough to require action. When this threshold is crossed, the MediaAgent generates an event message in the CommCell Console, and sends a MediaAgents (Disk Space Low) alert email if that alert is configured. It also begins deleting indexes on a least-recently-used basis until the percent of space used falls below the Index cleanup percent value.|
To set retention parameters for an index cache:
- From the CommCell Browser, expand Storage Resources > MediaAgents.
- Right-click the MediaAgent > Properties.
- Click the Catalog tab.
- Change the values of the retention parameters as required, then click OK.