A retrieve operation consists of a defined data flow between the StorageGRID Webscale system and the client. The system uses attributes to track the retrieval of the object from a Storage Node or, if necessary, from an Archive Node.
The Storage Node's LDR service queries the DDS service for the location of the object data and retrieves it from the source LDR service. Preferentially, retrieval is from disk. When there is no higher grade copy accessible, the retrieval request is directed to the Archive Node.
- The LDR service receives a retrieval request from the client application.
- The LDR service queries the DDS service for the object data location and metadata.
- LDR service forwards the retrieval request to the source LDR service.
- The source LDR service returns the object data and metadata from the queried LDR service and the system returns the object to the client application.