Creating policies within the Delphix Continuous Data Engine is an effective method to automate dataset management. Users can synchronize data, capture snapshots, and configure both retention and replica retention policies. This ensures that virtual databases are refreshed and data remains ready for use.
To set up policies, go to the Manage dropdown menu and select Policies. The Delphix Continuous Data Engine offers five main policy categories in relation to dataset objects:
SnapSync: Dictates the frequency of snapshot captures for a source database, known as a dSource.
VDB Snapshot: Determines how often snapshots are taken for a Virtual Database (VDB).
Retention: Specifies the duration for which snapshots and log files are kept for both dSources and VDBs.
VDB Refresh: Automates the refreshing of a VDB using either the latest snapshot or Timeflow logs, with 'None' being the default setting.
Replica Retention: Governs the length of time snapshots are preserved on replicated namespaces after deletion from the replication source. Snapshots are retained unless the source database is deleted. If the source is deleted, subsequent replication updates will remove the database and any snapshots retained on the target.
It is crucial to avoid setting conflicting policies. For instance, a NONE setting for the Snapshot policy can directly affect retention policies and lead to unexpected growth in VDB data. An example case could involve an engine that runs into a domain space issue because archive logs from a single VDB consume a significant portion of the storage pool.
This would be attributed to a NONE Snapshot policy being in place, coupled with a one-week log retention policy. The logs, necessary for provisioning from the only available snapshot, prevented the engine from enforcing the retention policy.