# US 2020/0401346 A1 · Storage system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0401346 A1 - Document ID: US20200401346A1 - Status: Published application - Kind: A1 - Application number: 16/801,334 - Filed: 2020-02-26 - Published: 2020-12-24 - Earliest claimed: 2019-06-20 - Assignees: Hitachi, Ltd. - Applicants: Hitachi, Ltd. - Inventors: Kentaro SHIMADA; Akira YAMAMOTO; Katsuya TANAKA - Web page: https://patentgrep.com/patent/US20200401346A1 ## CPC - G06F 3/0659: {Command handling arrangements, e.g. command buffers, queues, command scheduling} - G06F 3/067: {Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]} - G06F 3/0604: {Improving or facilitating administration, e.g. storage management} - G06F 3/061: {Improving I/O performance} - G06F 3/0658: {Controller construction arrangements} - G06F 3/0688: {Non-volatile semiconductor memory arrays} - G06F 3/0619: {in relation to data integrity, e.g. data losses, bit errors} - G06F 3/065: {Replication mechanisms} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A storage system includes a plurality of storage controllers and a drive box including one or more non-volatile storage devices. The drive box includes a memory on which reading and writing are performed in a unit different from a unit for reading and writing the one or more non-volatile storage devices, and which stores control information to be used by the plurality of storage controllers, and a memory controller that enables each storage controller of the plurality of storage controllers to exclusively read and write the control information of the memory by arbitrating accesses to the memory from the plurality of storage controllers. ## Claims ### Claim 1 A storage system comprising: a plurality of storage controllers; and a drive box that includes one or more non-volatile storage devices, wherein the drive box includes a memory on which reading and writing are performed in a unit different from a unit for reading and writing the one or more non-volatile storage devices, and which stores control information to be used by the plurality of storage controllers, and a memory controller that enables each storage controller of the plurality of storage controllers to exclusively read and write the control information of the memory by mediating access to the memory from each of the plurality of storage controllers. ### Claim 2 (depends on 1) The storage system according to claim 1, wherein the drive box includes a battery that supplies a power when external power feeding is stopped, and the memory retains contents of the memory by the power from the battery when the external power feeding is stopped. ### Claim 3 (depends on 2) The storage system according to claim 2, wherein the plurality of storage controllers stops operations when the external power feeding is stopped, and resumes the operations by using the control information stored in the memory when the external power feeding is restored. ### Claim 4 (depends on 1) The storage system according to claim 1, wherein the memory controller writes contents of the memory to the one or more non-volatile storage devices or another backup storage device within the drive box when external power feeding is stopped. ### Claim 5 (depends on 1) The storage system according to claim 1, wherein the memory includes a non-volatile memory element. ### Claim 6 (depends on 1) The storage system according to claim 1, further comprising: a plurality of memories including the memory; and a plurality of memory controllers including the memory controller, wherein each memory of the plurality of memories is connected to only one memory controller of the plurality of memory controllers, a first memory controller of the memory controllers transmits the information stored in the memory connected to the first memory controller to one or more other memory controllers, and each of the one or more other memory controllers stores the information received from the first memory controller in the memory connected to each of the one or more other memory controllers. ### Claim 7 (depends on 6) The storage system according to claim 6, wherein the first memory controller stores the information received from one storage controller of the plurality of storage controllers in the memory connected to the first memory controller according to an instruction from the one storage controller, and transmits the information received from the one storage controller to the one or more other memory controllers, each of the one or more other memory controllers transmits a write completion notification indicating that the writing of the information received from the first memory controller into the memory connected to each of the one or more other memory controllers is completed to the first memory controller, and the first memory controller notifies the one storage controller of a write completion of the information received from the one storage controller when the write completion notification is received from all the one or more other memory controllers. ### Claim 8 (depends on 1) The storage system according to claim 1, wherein the drive box includes a device protocol conversion unit, and each of the plurality of storage controllers transmits a command for the memory and a command for the one or more non-volatile storage devices according to an access protocol for accessing the memory, and the device protocol conversion unit converts the command for the one or more non-volatile storage devices into a command of an access protocol for accessing the one or more non-volatile storage devices. ### Claim 9 (depends on 1) The storage system according to claim 1, wherein the drive box includes a controller protocol conversion unit, each of the plurality of storage controllers transmits a command for the memory and a command for the one or more non-volatile storage devices according to an access protocol capable of being converted into both an access protocol for accessing the memory and an access protocol for accessing the one or more non-volatile storage devices, and the controller protocol conversion unit converts the command for the memory into a command of the access protocol for accessing the memory, and converts the command for the one or more non-volatile storage devices into a command of the access protocol for accessing the one or more non-volatile storage devices. ### Claim 10 A control method of a storage system, wherein the storage system includes a plurality of storage controllers, and a drive box that includes one or more non-volatile storage devices, and a memory on which reading and writing are performed in a unit different from a unit for reading and writing the one or more non-volatile storage devices and which stores control information to be used by the plurality of storage controllers, and the control method includes receiving an exclusive access command for the control information of the memory from one storage controller of the plurality of storage controllers, letting another access command received from the storage controller different from the one storage controller wait until the exclusive access command is completed, and executing the other access command after the exclusive access command is completed. ### Claim 11 (depends on 10) The control method according to claim 10, further comprising: writing contents of the memory to the one or more non-volatile storage devices or another backup non-volatile storage device within the drive box when external power feeding is stopped. ### Claim 12 (depends on 11) The control method according to claim 11, further comprising: waiting, by the plurality of storage controllers, for a restoration completion notification from the drive box when the external power feeding is restored after the external power feeding is stopped; re-storing, by the drive box, the contents of the memory written in the one or more non-volatile storage devices or another backup non-volatile storage device into the memory; transmitting, by the drive box, the restoration completion notification indicating that the contents of the memory are re-stored in the memory to each of the plurality of storage controllers; and resuming, by each of the plurality of storage controllers, an operation when the restoration completion notification is received. ### Claim 13 (depends on 10) The control method according to claim 10, wherein the drive box includes a plurality of memories including the memory, and the control method further includes writing information stored in one of the plurality of memories into the other one or more memories. ### Claim 14 (depends on 13) The control method according to claim 13, further comprising: writing the information stored in one memory of the plurality of memories by one storage controller of the plurality of storage controllers into the other one or more memories different from the one memory; and notifying the one storage controller that writing of the information is completed after writing of the information into the other one or more memories is completed. ### Claim 15 (depends on 10) The control method according to claim 10, wherein the drive box includes a memory controller, each of the plurality of storage controllers includes a processor that performs control and a processor memory connected to the processor, the control method further includes transmitting, by the processor of one storage controller of the plurality of storage controllers, information stored in the processor memory of the one storage controller to the memory controller, storing, by the memory controller, the transmitted information in the memory of the drive box, transmitting, by the memory controller, updated information to the processor of the one storage controller when the information stored in the memory is updated by the other processor different from the processor of the one storage controller, and reflecting, by the processor of the one storage controller, the updated information to the information stored in the processor memory of the one storage controller.