Following ingest, if an ILM rule’s Content Placement instructions are configured to make replicated copies of object data, copies are made and stored to disk through the LDR services of Storage Nodes that make up the configured storage pool.
Data flow
The ILM engine in the LDR controls replication and ensures that the correct number of copies are stored in the correct locations and for the correct amount of time.
- The ILM engine queries the ADC service to determine the best destination LDR service within the storage pool as defined by the ILM policy, and sends that LDR service a command to initiate replication.
- The destination LDR service queries the ADC service for the best source location and sends a replication request to the source LDR service.
- The source LDR service sends a copy to the destination LDR service.
- The destination LDR service notifies the CMS service that the object data has been stored.
- The ILM engine updates the DDS service with object location metadata.
Replication related attributes
The table shows the primary attributes used to track a replicated object:
| Component | Attribute changes |
|---|---|
| Evaluations: The total number of ILM evaluations that have been performed to date increases by one. | |
| Object Data: The amount of replicated object data stored on the object store increases by an amount roughly equivalent to the object's size in order to store an additional replicated copy. |