# US 2019/0317896 A1 · Storage device and storage method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0317896 A1 - Document ID: US20190317896A1 - Status: Published application - Kind: A1 - Application number: 16/368,917 - Filed: 2019-03-29 - Published: 2019-10-17 - Earliest claimed: 2018-04-17 - Assignees: Fujitsu Limited - Applicants: Fujitsu Limited - Inventors: Hidetoshi Nishi - Web page: https://patentgrep.com/patent/US20190317896A1 ## CPC - G06F 3/0683: {Plurality of storage devices} - G06F 12/0804: with main memory updating (G06F12/0806 takes precedence) - G06F 3/0604: {Improving or facilitating administration, e.g. storage management} - G06F 3/061: {Improving I/O performance} - G06F 3/0644: {Management of space entities, e.g. partitions, extents, pools} - G06F 3/065: {Replication mechanisms} - G06F 3/0656: {Data buffering arrangements} - G06F 3/068: {Hybrid storage device} - G06F 12/0246: {in block erasable memory, e.g. flash memory} - G06F 2212/1032: Reliability improvement, data loss prevention, degraded operation etc - G06F 2212/608: Details relating to cache mapping - G06F 2212/7203: Temporary buffering, e.g. using volatile buffer or dedicated buffer blocks - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A storage device includes a cache memory and a processor configured to perform, in accordance with an amount of dirty data stored in the cache memory, a determination of a first physical volume and a first logical volume placed in the first physical volume from the plurality of physical volumes and the plurality of logical volumes placed in the plurality of physical volumes, perform selection, from a first plurality of physical volumes in which the determined first logical volume is placed by mirroring, of a second physical volume other than the determined first physical volume, and perform selection, from the plurality of physical volumes, of a third physical volume other than the second plurality of physical volumes, and write data of the first logical volume read from the second physical volume, to the third physical volume, and delete the first logical volume from the determined first physical volume. ## Claims ### Claim 1 A storage device comprising: a cache memory; and a processor coupled to the cache memory and the processor configured to perform, in accordance with an amount of dirty data stored in the cache memory, the dirty data being not written back to a nonvolatile storage device, a determination of a first physical volume and a first logical volume placed in the first physical volume from the plurality of physical volumes and the plurality of logical volumes placed in the plurality of physical volumes, perform selection, from a first plurality of physical volumes in which the determined first logical volume is placed by mirroring, of a second physical volume other than the determined first physical volume as a read source, and perform selection, from the plurality of physical volumes, of a third physical volume other than the second plurality of physical volumes as a write destination, and write data of the first logical volume read from the second physical volume selected as the read source, to the third physical volume selected as the write destination, and delete the first logical volume from the determined first physical volume. ### Claim 2 (depends on 1) The storage device according to claim 1, wherein the amount of the dirty data includes a plurality of first values obtained by counting a number of the dirty data for each of the plurality of physical volumes, and a plurality of second values obtained by counting a number of the dirty data for each of the plurality of logical volumes. ### Claim 3 (depends on 2) The storage device according to claim 2, wherein the determination is performed in accordance with the plurality of first values, the plurality of second values, and a time stamp when each the dirty data is updated. ### Claim 4 (depends on 3) The storage device according to claim 3, wherein the determination includes determining the first physical volume of the first value no less than a first threshold value and determining the first logical volume having a largest second value among a first plurality of logical volumes placed in the determined first physical volume, and a time stamp of the dirty data related to the first logical volume indicates a time earlier than a certain period prior to a current time. ### Claim 5 (depends on 2) The storage device according to claim 2, wherein the selection of the third physical volume includes selecting the third physical volume having the smallest first value, from one or more physical volumes having storage capacity no less than an amount of the first logical volume among the plurality of physical volumes. ### Claim 6 (depends on 1) The storage device according to claim 1, wherein the determination is executed when a usage rate of the cache memory is no less than a second threshold value. ### Claim 7 A computer-implemented storage method comprising: determining, in accordance with an amount of dirty data stored in a cache memory, the dirty data being not written back to a nonvolatile storage device, a first physical volume and a first logical volume placed in the first physical volume from the plurality of physical volumes and the plurality of logical volumes placed in the plurality of physical volumes; selecting, from a first plurality of physical volumes in which the determined first logical volume is placed by mirroring, a second physical volume other than the determined first physical volume as a read source, and selecting, from the plurality of physical volumes, a third physical volume other than the second plurality of physical volumes as a write destination; and writing data of the first logical volume read from the second physical volume selected as the read source, to the third physical volume selected as the write destination, and deleting the first logical volume from the determined first physical volume. ### Claim 8 (depends on 7) The storage method according to claim 7, wherein the amount of the dirty data includes a plurality of first values obtained by counting a number of the dirty data for each of the plurality of physical volumes, and a plurality of second values obtained by counting a number of the dirty data for each of the plurality of logical volumes. ### Claim 9 (depends on 8) The storage method according to claim 8, wherein the determining is performed in accordance with the plurality of first values, the plurality of second values, and a time stamp when each the dirty data is updated. ### Claim 10 (depends on 9) The storage method according to claim 9, wherein the determining includes determining the first physical volume of the first value no less than a first threshold value and determining the first logical volume having a largest second value among a first plurality of logical volumes placed in the determined first physical volume, and a time stamp of the dirty data related to the first logical volume indicates a time earlier than a certain period prior to a current time. ### Claim 11 (depends on 8) The storage method according to claim 8, wherein the selecting of the third physical volume includes selecting the third physical volume having the smallest first value, from one or more physical volumes having storage capacity no less than an amount of the first logical volume among the plurality of physical volumes. ### Claim 12 (depends on 7) The storage method according to claim 7, wherein the determining is executed when a usage rate of the cache memory is no less than a second threshold value. ### Claim 13 A non-transitory computer-readable medium storing instructions executable by one or more computers, the instructions comprising: one or more instructions for determining, in accordance with an amount of dirty data stored in a cache memory, the dirty data being not written back to a nonvolatile storage device, a first physical volume and a first logical volume placed in the first physical volume from the plurality of physical volumes and the plurality of logical volumes placed in the plurality of physical volumes; one or more instructions for selecting, from a first plurality of physical volumes in which the determined first logical volume is placed by mirroring, a second physical volume other than the determined first physical volume as a read source, and selecting, from the plurality of physical volumes, a third physical volume other than the second plurality of physical volumes as a write destination; and one or more instructions for writing data of the first logical volume read from the second physical volume selected as the read source, to the third physical volume selected as the write destination, and deleting the first logical volume from the determined first physical volume.