Abstract: A method for managing metadata in a scale out storage system is disclosed. The system includes a plurality of nodes, a storage pool, first metadata that maps logical addresses of logical data blocks to corresponding content identifiers, and second metadata that maps content identifiers to corresponding physical addresses of physical data blocks in the storage pool and maintains a reference count. During an add-a-node operation, the processors are configured to move from the existing nodes to the new node some of its physical data blocks, their content identifiers and reference counts in the second metadata without accessing or altering the first metadata. A method is also disclosed to move a logical device from one node to another by de-activating the logical device's first metadata on the first node and activating and retrieving the logical device's first metadata on the second node.

Abstract: A method for managing metadata in a storage system is disclosed. The system includes a processor, a storage medium, a first metadata table that maps every data block's LBN to its unique content ID, and a second metadata table that maps every content ID to its PBN on the storage medium. During a data movement process, the processor is configured to determine the content ID of the data block and update its entry in the second metadata table without accessing the first metadata table. A method is also disclosed to reduce the size of the first metadata table. Only content ID is stored in the first metadata table and its LBN is determined by the metadata entry's relative position in the table. Metadata entries are stored in metadata blocks and deduplicated.

Abstract: A method for managing metadata in a storage system is disclosed. The system includes a processor, a storage medium, a first metadata table that maps every data block's LBN to its unique content ID, and a second metadata table that maps every content ID to its PBN on the storage medium. During a data movement process, the processor is configured to determine the content ID of the data block and update its entry in the second metadata table without accessing the first metadata table. A method is also disclosed to reduce the size of the first metadata table. Only content ID is stored in the first metadata table and its LBN is determined by the metadata entry's relative position in the table. Metadata entries are stored in metadata blocks and deduplicated.