# US 12,007,968 B2 · Full allocation volume to deduplication volume migration in a storage system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,007,968 B2 - Document ID: US12007968B2 - Status: Granted - Kind: B2 - Application number: 17/804,109 - Filed: 2022-05-26 - Published: 2023-11-30 - Granted: 2024-06-11 - Earliest claimed: 2022-05-26 - Assignees: International Business Machines Corporation - Applicants: International Business Machines Corporation - Inventors: Dominic Tomkins; Miles Mulholland; Eric John Bartlett; Alex Dicks - Web page: https://patentgrep.com/patent/US12007968B2 ## CPC - G06F 3/0608: {Saving storage space on storage systems} - G06F 16/215: Improving data quality; Data cleansing, e.g. de-duplication, removing invalid entries or correcting typographical errors - G06F 3/0641: {De-duplication techniques} - G06F 3/0688: {Non-volatile semiconductor memory arrays} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A method, computer program product, and computer system for full allocation volume to deduplication volume migration in a storage system. The method includes moving a physical allocation of stored data associated with a full allocation volume into a virtual address range in a deduplication domain and setting up the deduplication metadata to be a passthrough. The method then performs a background deduplication process on the virtual address range once populated with the physical allocations using a drive query hash interface to perform hash calculations on physical drives at which the data is stored. ## Claims ### Claim 1 A computer-implemented method for full allocation volume to deduplication volume migration in a storage system, said method carried out by one or more processors of a computer system and comprising: moving a physical allocation of stored data associated with a full allocation volume into a virtual address range in a deduplication domain and setting up the deduplication metadata to be a passthrough, wherein setting up the deduplication metadata to be a passthrough includes: creating a passthrough forward lookup structure for assimilation of the fully allocated volume to the deduplicated volume; and creating a stub backward lookup structure to be updated with deduplication metadata as the deduplicated volume is deduplicated; and performing a background deduplication process on the virtual address range once populated with the physical allocations using a drive query hash interface to perform hash calculations on physical drives at which the data is stored, wherein the virtual address range becomes a deduplicated volume for the data. ### Claim 2 (depends on 1) The method of claim 1, including refraining from moving data stored on the physical drives during the method. ### Claim 3 (depends on 1) The method of claim 1, wherein the physical allocation of stored data is a managed disk of data extents associated with physical data extents stored across a plurality of physical drives having excess compute capability at which hash calculations for the deduplication process are performed. ### Claim 4 (depends on 1) The method of claim 1, including pausing input/output operations whilst moving a physical allocation of stored data associated with a full allocation volume into a virtual address range in a deduplication domain. ### Claim 5 (depends on 1) The method of claim 1, including reserving, by a deduplication layer, the virtual address range in the deduplication domain to which the physical allocations associated with the fully allocated volume are moved. ### Claim 6 (depends on 1) The method of claim 1, wherein moving a physical allocation of stored data associated with a full allocation volume into a virtual address range in a deduplication domain is carried out by a virtualization layer and includes marking the volume as a deduplicated volume and activating a deduplication layer and the passthrough metadata. ### Claim 7 (depends on 1) The method of claim 1, wherein performing a background deduplication process includes iterating over grains of the deduplication volume by a deduplication layer with locking of a grain to an input/output operation during a grain deduplication. ### Claim 8 (depends on 7) The method of claim 7, wherein iterating over grains includes: when a grain is a deduplication hit, creating referrer metadata on a passthrough forward lookup structure to point to source metadata and marking the grain as invalid; when a grain is a deduplication miss, storing a hash for the grain in a deduplication fingerprint database, creating source metadata on the passthrough forward lookup structure to point to grain on data disk; and for all grains, updating a backward lookup structure with invalidations or virtual addresses. ### Claim 9 (depends on 1) The method of claim 1, including carrying out hash calculations at a Flash Core Module (FCM) on the drive layer without reading the data from outside the FCM. ### Claim 10 A system for full allocation volume to deduplication volume migration in a storage system including a processor and a memory configured to provide computer program instructions to the processor to execute the function of the components, the system comprising: a physical allocation moving component in a virtualization layer for moving a physical allocation of stored data associated with a full allocation volume into a virtual address range in a deduplication domain; a deduplication metadata setting up component for setting up the deduplication metadata to be a passthrough, wherein setting up the deduplication metadata to be a passthrough includes: creating a passthrough forward lookup structure for assimilation of the fully allocated volume to the deduplicated volume; and creating a stub backward lookup structure to be updated with deduplication metadata as the deduplicated volume is deduplicated; and a deduplication component of a deduplication layer for performing a background deduplication process on the virtual address range once populated with the physical allocations using a drive query hash interface to perform hash calculations on physical drives at which the data is stored, wherein the virtual address range becomes a deduplicated volume for the data. ### Claim 11 (depends on 10) The system of claim 10, wherein the physical allocation of stored data is a managed disk of data extents associated with physical data extents stored across a plurality of physical drives having excess compute capability at which hash calculations for the deduplication process are performed. ### Claim 12 (depends on 10) The system of claim 10, including a pausing component for pausing input/output operations whilst moving a physical allocation of stored data associated with a full allocation volume into a virtual address range in a deduplication domain. ### Claim 13 (depends on 10) The system of claim 10, including a reserving component in the deduplication layer for reserving the virtual address range in the deduplication domain to which the physical allocations associated with the fully allocated volume are moved. ### Claim 14 (depends on 10) The system of claim 10, wherein the physical allocation moving component includes marking the volume as a deduplicated volume and activating a deduplication layer and the passthrough metadata. ### Claim 15 (depends on 10) The system of claim 10, wherein the deduplication component includes a grain iterating component for iterating over grains of the deduplication volume by a deduplication layer with locking of a grain to an input/output operation during a grain deduplication. ### Claim 16 (depends on 15) The system of claim 15, wherein the grain iterating component includes: a hit component for, when a grain is a deduplication hit, creating referrer metadata on a passthrough forward lookup structure to point to source metadata and marking the grain as invalid; a miss component for, when a grain is a deduplication miss, storing a hash for the grain in a deduplication fingerprint database, creating source metadata on the passthrough forward lookup structure to point to grain on data disk; and a backward lookup update component for updating a backward lookup structure with invalidations or virtual addresses. ### Claim 17 (depends on 10) The system of claim 10, wherein the plurality of physical drives are Flash Core Modules (FCM). ### Claim 18 A computer program product for full allocation volume to deduplication volume migration in a storage system, the non-transitory computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the processor to: move a physical allocation of stored data associated with a full allocation volume into a virtual address range in a deduplication domain and set up the deduplication metadata to be a passthrough, wherein setting up the deduplication metadata to be a passthrough includes: creating a passthrough forward lookup structure for assimilation of the fully allocated volume to the deduplicated volume; and creating a stub backward lookup structure to be updated with deduplication metadata as the deduplicated volume is deduplicated; and perform a background deduplication process on the virtual address range once populated with the physical allocations using a drive query hash interface to perform hash calculations on physical drives at which the data is stored, wherein the virtual address range becomes a deduplicated volume for the data.