# US 7,412,543 B2 · Method for controlling storage system, and storage control apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,412,543 B2 - Document ID: US7412543B2 - Status: Granted - Kind: B2 - Application number: 11/338,797 - Filed: 2006-01-25 - Published: 2006-07-27 - Granted: 2008-08-12 - Earliest claimed: 2002-04-26 - Assignees: Hitachi, Ltd. - Inventors: Hiroshi Ohno; Kouji Arai; Toshio Nakano; Hideo Tabuchi; Akinobu Shimada; Ai Satoyama; Yasutomo Yamamoto; Yoshiaki Eguchi - Web page: https://patentgrep.com/patent/US7412543B2 ## CPC - G06F 3/061: {Improving I/O performance} - G06F 3/0607: {by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device} - G06F 3/0635: {by changing the path, e.g. traffic rerouting, path reconfiguration} - G06F 3/064: {Management of blocks} - G06F 3/0659: {Command handling arrangements, e.g. command buffers, queues, command scheduling} - G06F 3/0665: {at area level, e.g. provisioning of virtual or logical volumes} - G06F 3/067: {Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]} - G06F 3/0689: {Disk arrays, e.g. RAID, JBOD} - G06F 12/0866: for peripheral storage systems, e.g. disk cache - G06F 2212/312: In storage controller - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A method for controlling a storage system including a host computer, and a first and a second storage control apparatuses each receiving a data input/output request from the host computer and executing a data input/output process for a storage device in response to the request, comprises connecting a first communication path between the host computer and the first apparatus; connecting a second communication path between the first apparatus and the second apparatus; receiving by the first apparatus a first data input/output request from the host computer through the first path; when the first apparatus has judged that the first request is not for the first apparatus, transmitting by the first apparatus a second data input/output request corresponding to the first request, to the second apparatus through the second path; and by the second apparatus, receiving the second request and executing a data input/output process corresponding to the second request received. ## Claims ### Claim 1 A first storage control apparatus adapted to be coupled to a plurality of storage control apparatuses, at least one of said plurality of storage control apparatuses including a plurality of storage devices and a data read/write control unit executing data read/write processes to said plurality of storage devices based on a Redundant Array of Independent Disks (RAID) scheme, said first storage control apparatus comprising: a control unit transmitting a request corresponding to a data write request or a data read request received from a host computer with reference to mapping information between a first Logical Unit Number (LUN), designated by said data write request or said data read request received from said host computer, and a second LUN of a logical volume from/to which a second storage control apparatus of said plurality of storage control apparatuses executes data read/write processes; wherein said control unit of said first storage control apparatus receives a predetermined copy command related to said first LUN and executes a copy process from said second storage control apparatus to a third storage control apparatus of said plurality of storage control apparatuses, the second storage control apparatus being unable to execute said predetermined copy command. ### Claim 2 (depends on 1) A first storage control apparatus according to claim 1, wherein said control unit of said first storage control apparatus transmits a read command, which said second storage control apparatus is capable of executing, to said second storage control apparatus in order to use data, which is read from said logical volume of said second storage control apparatus, in said copy process. ### Claim 3 (depends on 1) A first storage control apparatus according to claim 1, wherein said control unit of said first storage control apparatus comprises a cache memory, and wherein said control unit of said first storage control apparatus, in said copy process, stores data, read from said logical volume of said second storage control apparatus, in said cache memory and transmits data stored in said cache memory to said third storage control apparatus. ### Claim 4 (depends on 3) A first storage control apparatus according to claim 3, wherein said cache memory stores data corresponding to said data write request received from said host computer. ### Claim 5 (depends on 3) A first storage control apparatus according to claim 3, comprising: a plurality of storage devices; wherein said control unit of said first storage control apparatus executes data read/write processes to said plurality of storage devices of said first storage control apparatus based on the RAID scheme. ### Claim 6 (depends on 3) A first storage control apparatus according to claim 3, wherein said predetermined copy command is a command defined in Small Computer System Interface (SCSI) standards. ### Claim 7 (depends on 6) A first storage control apparatus according to claim 6, wherein said predetermined copy command is an extended copy command defined in SCSI standards. ### Claim 8 A control unit of a first storage control apparatus adapted to be coupled to a plurality of storage control apparatuses, at least one of said plurality of storage control apparatuses including a plurality of storage devices and a data read/write control unit executing data read/write processes to said plurality of storage devices based on a Redundant Array of Independent Disks (RAID) scheme, wherein said control unit of said first storage control apparatus transmits a request corresponding to a data write request or a data read request received from a host computer with reference to a mapping information between a first Logical Unit Number (LUN), designated by said data write request or said data read request received from said host computer, and a second LUN of a logical volume from/to which a second storage control apparatus of said plurality of storage control apparatuses executes data read/write processes, and wherein said control unit of said first storage control apparatus receives a predetermined copy command related to said first LUN and executes a copy process from said second storage control apparatus to a third storage control apparatus of said plurality of storage control apparatuses, the second storage control apparatus being unable to execute said predetermined copy command. ### Claim 9 (depends on 8) A control unit according to claim 8, wherein said control unit of said first storage control apparatus transmits a read command, which said second storage control apparatus is capable of executing, to said second storage control apparatus in order to use data, which is read from said logical volume of said second storage control apparatus, in said copy process. ### Claim 10 (depends on 8) A control unit according to claim 8, comprising: a cache memory, and wherein said control unit of said first storage control apparatus, in said copy process, stores data, read from said logical volume of said second storage control apparatus, in said cache memory and transmits data stored in said cache memory to said third storage control apparatus. ### Claim 11 (depends on 10) A control unit according to claim 10, wherein said cache memory stores data corresponding to said data write request received from said host computer. ### Claim 12 (depends on 8) A control unit according to claim 8, wherein said control unit of said first storage control apparatus executes data read/write processes to a plurality of storage devices of said first storage control apparatus based on the RAID scheme. ### Claim 13 (depends on 8) A control unit according to claim 8, wherein said predetermined copy command is a command defined in Small Computer System Interface (SCSI) standards. ### Claim 14 (depends on 13) A control unit according to claim 13, wherein said predetermined copy command is an extended copy command defined in SCSI standards. ### Claim 15 A control method of a first storage control apparatus adapted to be coupled to a plurality of storage control apparatuses, at least one of said plurality of storage control apparatuses including a plurality of storage devices and a data read/write control unit executing data read/write processes to said plurality of storage devices based on a Redundant Array of Independent Disks (RAID) scheme, said control method comprising the steps of: transmitting a request corresponding to a data write request or a data read request received from a host computer with reference to a mapping information between a first Logical Unit Number (LUN), designated by said data write request or said data read request received from said host computer, and a second LUN of a logical volume from/to which a second storage control apparatus of said plurality of storage control apparatuses executes data read/write processes, receiving a predetermined copy command related to said first LUN, and executing a copy process from said second storage control apparatus to a third storage control apparatus of said plurality of storage control apparatuses, the second storage control apparatus being unable to execute said predetermined copy command. ### Claim 16 (depends on 15) A control method according to claim 15, further comprising the step of: transmitting a read command, which said second storage control apparatus is capable of executing, to said second storage control apparatus in order to use data, which is read from said logical volume of said second storage control apparatus, in said copy process. ### Claim 17 (depends on 15) A control method according to claim 15, further comprising the steps of: in said copy process, storing data, read from said logical volume of said second storage control apparatus, in a cache memory, and transmitting data stored in said cache memory to said third storage control apparatus. ### Claim 18 (depends on 17) A control method according to claim 17, wherein said cache memory stores data corresponding to said data write request received from said host computer. ### Claim 19 (depends on 15) A control method according to claim 15, further comprising the step of: executing data read/write processes to a plurality of storage devices of said first storage control apparatus based on the RAID scheme. ### Claim 20 (depends on 15) A control method according to claim 15, wherein said predetermined copy command is a command defined in Small Computer System Interface (SCSI) standards. ### Claim 21 (depends on 20) A control method according to claim 20, wherein said predetermined copy command is an extended copy command defined in SCSI standards.