# US 2021/0334181 A1 · Remote copy system and remote copy management method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0334181 A1 - Document ID: US20210334181A1 - Status: Published application - Kind: A1 - Application number: 17/015,192 - Filed: 2020-09-09 - Published: 2021-10-28 - Earliest claimed: 2020-04-28 - Assignees: Hitachi, Ltd. - Applicants: Hitachi, Ltd. - Inventors: Ai SATOYAMA; Akira DEGUCHI - Web page: https://patentgrep.com/patent/US20210334181A1 ## CPC - G06F 11/2069: {Management of state, configuration or failover} - G06F 11/1471: involving logging of persistent data for recovery - G06F 11/2074: {Asynchronous techniques} - G06F 11/2094: {Redundant storage or storage space (G06F11/2056 takes precedence)} - G06F 11/2097: {maintaining the standby controller/processing unit updated (initialisation or re-synchronisation thereof G06F11/1658 and subgroups)} - G06F 16/10: File systems; File servers - H04L 67/1097: for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS] - G06F 2201/84: Using snapshots, i.e. a logical point-in-time copy of the data - H04L 67/1095: Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A failure in a main site is recovered by operating in the same operational environment as a sub site. A remote copy system includes: a first storage system providing a main site; and a second storage system providing a sub site. A storage controller stores data and an operation processed in the main site as a main site journal, sends the main site journal to the sub site for sequential processing, stores data and an operation processed in the sub site as a sub site journal after a failover to the sub site is performed, and cancels an unreflected operation that is not processed in the sub site after being stored in the main site journal prior to the failover in the main site and sequentially processes the sub site journal in the main site, when a failback to the main site is performed. ## Claims ### Claim 1 A remote copy system, comprising: a first storage system that provides a main site; and a second storage system that provides a sub site, wherein a storage controller of the storage system performs remote copy by storing data and an operation processed in the main site in a journal volume in the first storage system as a main site journal, and by sending the main site journal to the sub site for sequentially performing processing, stores data and an operation processed in the sub site in a journal volume in the second storage system as a sub site journal after a failover from the main site to the sub site is performed, and cancels an unreflected operation that is not processed in the sub site after being stored in the main site journal prior to the failover in the main site, and sequentially processes the sub site journal in the main site, when a failback from the sub site to the main site is performed. ### Claim 2 (depends on 1) The remote copy system according to claim 1, wherein the storage controller deletes a snapshot when generation of the snapshot performed in the main site is the unreflected operation. ### Claim 3 (depends on 2) The remote copy system according to claim 2, wherein the storage controller changes a reference destination of another snapshot when the snapshot to be deleted is referenced by the another snapshot. ### Claim 4 (depends on 1) The remote copy system according to claim 1, wherein the storage controller excludes deletion of a snapshot from a cancellation target when the deletion of the snapshot performed in the main site is an unreflected operation, and the sub site uses the snapshot between the failover and the failback. ### Claim 5 (depends on 1) The remote copy system according to claim 1, wherein when executing an operation that cannot be cancelled at the time of failback in the main site, the storage controller sends the operation to the sub site without storing the operation in the main site journal for performing processing. ### Claim 6 (depends on 1) The remote copy system according to claim 1, wherein regarding writing processing of unreflected data that are not processed in the sub site after being stored in the main site journal prior to the failover, when the sub site does not perform writing processing of data with respect to the same portion until the failback, the storage controller generates a write request to the main site by using the data at the same portion of the sub site. ### Claim 7 (depends on 1) The remote copy system according to claim 1, wherein the storage controller determines whether to recover the main site using the main site journal and the sub site journal, or to send all the data of the sub site to the main site for performing recovery, depending on a type of abnormality triggering the failover. ### Claim 8 A remote copy management method for managing remote copy between a first storage system that provides a main site and a second storage system that provides a sub site, the method comprising: performing, by a storage controller of the storage system, the remote copy by storing data and an operation processed in the main site in a journal volume in the first storage system as a main site journal, and by sending the main site journal to the sub site for sequentially performing processing; storing, by the storage controller of the storage system, data and an operation processed in the sub site in a journal volume in the second storage system as a sub site journal after a failover from the main site to the sub site is performed, and cancelling, by the storage controller of the storage system, an unreflected operation that is not processed in the sub site after being stored in the main site journal prior to the failover in the main site, and sequentially processing the sub site journal in the main site, when a failback from the sub site to the main site is performed.