how-purge-expired-data.md

title	summary	related	reviewed
Automatic Expiration of Data	Configuring ServiceControl's data retention policy	nservicebus/recoverability nservicebus/operations/auditing servicecontrol/audit-instances/persistence	2022-10-18

ServiceControl stores audit and error data. Any audit and error data that is older than the specified thresholds is deleted from the embedded RavenDB. The expiration thresholds for both faulted and audited messages must be set during installation. These values can be modified later by launching ServiceControl Management and editing the configuration settings for the instance.

Note

The expiration process curates only the data in the embedded RavenDB. Audit and error forwarding queues are not curated or managed by ServiceControl. To turn these settings off, launch ServiceControl Management and edit the configuration settings for the instance.

Warning

The database will not automatically shrink in size after reducing the retention period. Ensure ServiceControl had time to purge all expired messages and then compact the database.

Differences in message retention implementations

The expiration of error and audit data is implemented by a recurring task that checks and deletes expired documents. Changing the expiration setting results in it being picked up the next time the service is run. In ServiceControl.Audit version 4.26 and above expiration is handled by the database automatically. Each audited message contains a metadata key that tells the database when to remove it. When the expiration setting changes, the new value is applied only to new audit data. Metadata for messages that were previously ingested is not changed. Only new audited messages are affected by the change to the expiration setting.