| 摘要 |
<p>Digital objects within a fixed-content storage cluster use a page mapping table and a hash-to-UID table to store a representation of each object. For each object stored within the cluster, a record in the hash-to-UID table stores the object's hash value and its unique identifier (or portions thereof). To detect a duplicate of an object, a portion of its hash value is used as a key into the page mapping table. The page mapping table indicates a node holding a hash-to-UID table indicating currently stored objects in a particular page range. Finding the same hash value but with a different unique identifier in the table indicates that a duplicate of an object exists. Portions of the hash value and unique identifier may be used in the hash-to-UID table. Unneeded duplicate objects are deleted by copying their metadata to a manifest and then redirecting their unique identifiers to point at the manifest.</p> |
