Method and apparatus for on-disk deduplication metadata for a deduplication file system

An article of manufacture having one or more non-transitory computer readable storage media storing executable instructions thereon which when executed cause a system to perform a method comprising:

• reading deduplication metadata from a first memory of a deduplication computing system, wherein the deduplication metadata comprises a deduplication metadata hash table, wherein the deduplication metadata hash table comprises a plurality of slots with deduplication metadata entries distributed among the plurality of slots based on unique identifiers from the deduplication metadata entries, and wherein the at least a portion of the unique identifiers are mask values each comprising a lower portion of bits of a unique identifier, and wherein the mask value is an index to the slots of the deduplication metadata table;
• maintaining deduplicated data for a file system of the deduplication computing system in a second memory;
• maintaining the deduplication metadata that describes the deduplicated data of the file system in the first memory of the deduplication computing system, wherein the first memory is a different type of memory and separated from the second memory in the deduplication computing system;
• in response to receipt of a request by the deduplication computing system to perform a first operation with deduplicated data of the file system in the second memory, accessing the deduplication metadata in the first memory;
• dynamically resizing the deduplication metadata hash table to a new size based on one or more runtime conditions associated with an amount of utilization of the deduplication metadata hash table at runtime;
• allocating or deallocating slots for the deduplication metadata hash table based on the new size;
• and
• redistributing deduplication metadata entries to slots of the deduplication metadata hash table based on mask values associated with unique identifiers from the deduplication metadata entries.

A deduplication computing system comprising:

• a first memory to store deduplication metadata;
• a second memory to store deduplicated data;
• and
• a processor coupled with the first memory and the second memory to
• read the deduplication metadata from the first memory, wherein the deduplication metadata comprises a deduplication metadata hash table, wherein the deduplication metadata hash table comprises a plurality of slots with deduplication metadata entries distributed among the plurality of slots based on unique identifiers from the deduplication metadata entries, and wherein the at least a portion of the unique identifiers are mask values each comprising a lower portion of bits of a unique identifier, and wherein the mask value is an index to the slots of the deduplication metadata table,
• maintain the deduplicated data for a file system of the deduplication computing system in the second memory,
• maintain the deduplication metadata that describes the deduplicated data of the file system in the first memory of the deduplication computing system, wherein the first memory is a different type of memory and separated from the second memory in the deduplication computing system,
• in response to receipt of a request by the deduplication computing system to perform a first operation with deduplicated data of the file system in the second memory, access the deduplication metadata in the first memory;
• dynamically resize the deduplication metadata hash table to a new size based on one or more runtime conditions associated with an amount of utilization of the deduplication metadata hash table at runtime;
• allocating or deallocating slots for the deduplication metadata hash table based on the new size;
• and
• redistributing deduplication metadata entries to slots of the deduplication metadata hash table based on mask values associated with unique identifiers from the deduplication metadata entries.