# US 10,769,117 B2 · Effective handling of HSM migrated files and snapshots > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,769,117 B2 - Document ID: US10769117B2 - Status: Granted - Kind: B2 - Application number: 15/874,240 - Filed: 2018-01-18 - Published: 2019-07-18 - Granted: 2020-09-08 - Earliest claimed: 2018-01-18 - Assignees: International Business Machines Corporation - Applicants: International Business Machines Corporation - Inventors: Mauro Cruciani; Christian Mueller; Dominic Mueller-Wicke; Eirini Petraki; Sabine U. Steinhauer - Web page: https://patentgrep.com/patent/US10769117B2 ## CPC - G06F 16/185: Hierarchical storage management [HSM] systems, e.g. file migration or policies thereof (details of archiving G06F16/11) - G06F 3/0685: {Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays} - G06F 11/1448: {Management of the data involved in backup or backup restore} - G06F 16/174: Redundancy elimination performed by the file system (error detection or correction of the data by redundancy in operations G06F11/14) - G06F 3/0605: {by facilitating the interaction with a user or administrator} - G06F 3/0649: {Lifecycle management} - G06F 11/1464: {for networked environments} - G06F 16/119: {Details of migration of file systems (migration mechanisms in storage systems G06F3/0647)} - G06F 16/162: {Delete operations (erasing in storage systems G06F3/0652)} - G06F 16/172: Caching, prefetching or hoarding of files - G06F 2201/84: Using snapshots, i.e. a logical point-in-time copy of the data - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A method for handling snapshots together with migrated files in a hierarchical storage management may be provided. The method comprises managing files using a first-tier storage and a second-tier storage. The files are organized in a managed file system—e.g., a hierarchically managed file system—in the first-tier storage. The method comprises further creating a snapshot of a portion of the files of the first-tier storage, thereby creating a hidden directory in the file system, deleting a migrated file, and moving the stub file relating to the file to be deleted in the first-tier storage to the hidden directory. ## Claims ### Claim 1 A method for handling snapshots together with migrated files in a hierarchical storage management system, said method comprising: managing files using a first-tier storage and a second-tier storage, wherein said files are organized in a file system in said first-tier storage, wherein said file system is a managed file system; creating a snapshot of a portion of said files of said first-tier storage, and thereby creating a hidden directory in said file system; deleting a file, wherein said file is a migrated file, wherein the migrated file is copied from the first-tier storage to the second-tier storage; and moving a stub file relating to said file to be deleted in said first-tier storage to said hidden directory, wherein the stub file includes metadata attributes that provide a link to the migrated file located in the second-tier storage, wherein the link grants access to the migrated file. ### Claim 2 (depends on 1) The method according to claim 1, also comprising: determining a creation time of said migrated file to be deleted; and determining snapshot versions in which said migrated file to be deleted is part of. ### Claim 3 (depends on 2) The method according to claim 2, also comprising: adding metadata to said moved stub file in a hidden folder, said metadata being indicative of said determined snapshots. ### Claim 4 (depends on 3) The method according to claim 3, also comprising: deleting a snapshot by: determining stub files in said hidden directory, said stub files relating to said snapshot to be deleted; upon said snapshot not being said last one, deleting said related metadata; and deleting said snapshot. ### Claim 5 (depends on 4) The method according to claim 4, wherein said deleting a snapshot also comprises: upon said snapshot being said last one, deleting said related stub file in said hidden folder. ### Claim 6 (depends on 1) The method according to claim 1, wherein said creating said hidden directory is only performed for a first snapshot to be created. ### Claim 7 (depends on 1) The method according to claim 1, wherein said managed file system is an encrypted managed file system. ### Claim 8 (depends on 1) The method according to claim 1, wherein said managing said files is based on a data management application programming interface. ### Claim 9 (depends on 1) The method according to claim 1, wherein said snapshot is a software snapshot. ### Claim 10 A system for handling snapshots together with migrated files in a hierarchical storage management, said system comprising: a first-tier storage and a second-tier storage adapted for managing files, wherein said files are organized in a file system in said first-tier storage, wherein said file system is a managed file system; a processing unit comprising: a snapshot unit creating a snapshot of a portion of said files of said first-tier storage, and thereby creating a hidden directory in said file system; a deletion module deleting a file in said first-tier storage, wherein said file is a migrated file, wherein the migrated file is copied from the first-tier storage to the second-tier storage; and a movement unit moving a stub file relating to said file to be deleted in said first-tier storage to said hidden directory, wherein the stub file includes metadata attributes that provide a link to the migrated file located in the second-tier storage, wherein the link grants access to the migrated file. ### Claim 11 (depends on 10) The system according to claim 10, also comprising: a time determination unit adapted for determining a creation time of said migrated file to be deleted; and a version determination unit adapted for determining snapshot versions in which said migrated file to be deleted is part of. ### Claim 12 (depends on 11) The system according to claim 11, wherein said snapshot unit is adapted for: adding metadata to said moved stub file in a hidden folder, said metadata being indicative of said determined snapshots. ### Claim 13 (depends on 12) The system according to claim 12, also comprising: a snapshot deletion unit adapted for deleting a snapshot by: determining stub files in said hidden directory, said stub files relating to said snapshot to be deleted; upon said snapshot not being said last one; deleting said related metadata; and deleting said snapshot. ### Claim 14 (depends on 13) The system according to claim 13, wherein said snapshot deletion unit, when deleting a snapshot, is also adapted for: upon said snapshot being said last one; deleting said related stub file in said hidden folder. ### Claim 15 (depends on 10) The system according to claim 10, wherein said snapshot unit is also adapted for creating said hidden directory only for a first snapshot to be created. ### Claim 16 (depends on 10) The system according to claim 10, wherein said managed file system is an encrypted managed file system. ### Claim 17 (depends on 10) The system according to claim 10, wherein said managing said files is based on a data management application programming interface. ### Claim 18 (depends on 10) The system according to claim 10, wherein said snapshot is a software snapshot. ### Claim 19 A computer program product for handling snapshots together with migrated files in a hierarchical storage management, said computer program product comprising a computer readable storage medium having program instructions embodied therewith, said program instructions being executable by one or more computing systems to cause said one or more computing systems to: manage files using a first-tier storage and a second-tier storage, wherein said files are organized in a file system in said first-tier storage, wherein said file system is a managed file system; creating a snapshot of a portion of said files of said first-tier storage, and thereby creating a hidden directory in said file system; deleting a file in said first-tier storage, wherein said file is a migrated file, wherein the migrated file is copied from the first-tier storage to the second-tier storage; and moving a stub file relating to said file to be deleted in said first-tier storage to said hidden directory, wherein the stub file includes metadata attributes that provide a link to the migrated file located in the second-tier storage, wherein the link grants access to the migrated file.