# US 2014/0195760 A1 · Storage apparatus and data management method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0195760 A1 - Document ID: US20140195760A1 - Status: Published application - Kind: A1 - Application number: 14/199,302 - Filed: 2014-03-06 - Published: 2014-07-10 - Earliest claimed: 2012-11-19 - Assignees: Hitachi, Ltd. - Applicants: Hitachi, Ltd. - Inventors: Koji IWAMITSU; Hiroaki AKUTSU; Daisuke ENDO - Web page: https://patentgrep.com/patent/US20140195760A1 ## CPC - G06F 3/0659: {Command handling arrangements, e.g. command buffers, queues, command scheduling} - G06F 3/0604: {Improving or facilitating administration, e.g. storage management} - G06F 3/0611: {in relation to response time} - G06F 3/0613: {in relation to throughput} - G06F 3/0647: {Migration mechanisms} - G06F 3/0649: {Lifecycle management} - G06F 3/067: {Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]} - G06F 3/0673: {Single storage device} - G06F 3/0685: {Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays} - G06F 13/102: {where the program performs an interfacing function, e.g. device driver (G06F13/105 takes precedence; contention policies within device drivers G06F9/4881; scheduling within device drivers G06F9/52)} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A storage apparatus for which a hierarchical data management system is adopted is designed so that when receiving a read request for a first logical area to which a first storage area of a first storage device in a virtual volume is allocated, whether or not to migrate data in a first storage area of the first storage device, to a storage area of a second storage device is decided according to an access frequency to the first logical area in synchronization with the read request. When it is decided that the data stored in the first storage area of the first storage device should be migrated to the storage area of the second storage device, the data is migrated to a second storage area of the second storage device and the second storage area thereof is allocated to the first logical area in the virtual volume. ## Claims ### Claim 1 A storage apparatus being coupled to a host computer, comprising: a plurality of storage devices including a first storage device and a second storage device whose performance is higher than that of the first storage device; and a controller providing a virtual volume including a plurality of logical areas to the host computer, and allocating at least one of a plurality of storage areas in the plurality of storage devices to a logical area of the virtual volume after receiving a write request to the logical area of the virtual volume; wherein, the controller is configured to: determine, in response to receiving a read request or a write request to the virtual volume, whether or not to migrate data in a first storage area of the first storage device allocated to a first logical area in the first virtual volume corresponding to the read request or the write request, to a second storage area of the second storage device based on an access frequency corresponding to the data; and migrate the data in the first storage area of the first storage device to the second storage area of the second storage device according to a result of the determination; and allocate the second storage area of the second storage device to the first logical area in the virtual volume. ### Claim 2 (depends on 1) A storage apparatus according to claim 1, wherein the second storage device is a SSD (Solid State Drive). ### Claim 3 (depends on 1) A storage apparatus according to claim 1, wherein if the controller determines not to migrate the data in the first storage area, the controller maintains the data in the first storage area and keeps allocating the first storage area to the first logical area. ### Claim 4 (depends on 1) A storage apparatus according to claim 1, wherein a third storage area of the second storage device is allocated to a second logical area in the first virtual volume for storing data of the second logical area while the first storage area of the first storage device is allocated to the first logical area in the first virtual volume for storing data of the first logical area. ### Claim 5 (depends on 4) A storage apparatus according to claim 4, wherein an access frequency of the data of the second logical area is higher than an access frequency of the data of the first logical area. ### Claim 6 (depends on 1) A storage apparatus according to claim 1, wherein when the second storage device does not have enough capacity for storing data migrated from the first storage area of the first storage device, the controller is configured to: determine whether or not to migrate data in a third storage area of the second storage device, which is allocated to a second logical area in the first virtual volume, to the first storage device according to an access frequency; and migrate data in the third storage area of the second storage device to a fourth storage area of the first storage device when the controller determines the data in the third storage area of the first storage device is migrated to the first storage device; and allocate the fourth storage area of the first storage device to the second logical area in the virtual volume. ### Claim 7 A method of managing a storage apparatus coupled to a host computer, the storage apparatus having a plurality of storage devices including a first storage device and a second storage device whose performance is higher than that of the first storage device, and a controller which provides a virtual volume including a plurality of logical areas to the host computer, and which allocates at least one of a plurality of storage areas in the plurality of storage devices to a logical area of the virtual volume after receiving a write request to the logical area of the virtual volume, the method comprising: determining, in response to receiving a read request or a write request to the virtual volume, whether or not to migrate data in a first storage area of the first storage device allocated to a first logical area in the first virtual volume corresponding to the read request or the write request, to a second storage area of the second storage device based on an access frequency corresponding to the data; and migrating the data in the first storage area of the first storage device to the second storage area of the second storage device according to a result of the determination; and allocating the second storage area of the second storage device to the first logical area in the virtual volume. ### Claim 8 (depends on 7) The method according to claim 7, wherein the second storage device is a SSD (Solid State Drive). ### Claim 9 (depends on 7) The method according to claim 7, further comprising: upon determining not to migrate the data in the first storage area, maintaining the data in the first storage area and continuing to allocate the first storage area to the first logical area. ### Claim 10 (depends on 7) The method according to claim 7, wherein a third storage area of the second storage device is allocated to a second logical area in the first virtual volume for storing data of the second logical area while the first storage area of the first storage device is allocated to the first logical area in the first virtual volume for storing data of the first logical area. ### Claim 11 (depends on 10) The method according to claim 10, wherein an access frequency of the data of the second logical area is higher than an access frequency of the data of the first logical area. ### Claim 12 (depends on 7) The method according to claim 7, further comprising: when the second storage device does not have enough capacity for storing data migrated from the first storage area of the first storage device, determining whether or not to migrate data in a third storage area of the second storage device, which is allocated to a second logical area in the first virtual volume, to the first storage device according to an access frequency, migrating data in the third storage area of the second storage device to a fourth storage area of the first storage device upon determining that the data in the third storage area of the first storage device is migrated to the first storage device, and allocating the fourth storage area of the first storage device to the second logical area in the virtual volume.