# US 10,310,984 B2 · Storage apparatus and storage control method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,310,984 B2 - Document ID: US10310984B2 - Status: Granted - Kind: B2 - Application number: 15/510,594 - Filed: 2014-10-09 - Published: 2017-07-06 - Granted: 2019-06-04 - Earliest claimed: 2014-10-09 - Assignees: Hitachi, Ltd. - Applicants: Hitachi, Ltd. - Inventors: Atsushi Kawamura - Web page: https://patentgrep.com/patent/US10310984B2 ## CPC - G06F 12/10: Address translation - G06F 12/0246: {in block erasable memory, e.g. flash memory} - G06F 12/1027: using associative or pseudo-associative address translation means, e.g. translation look-aside buffer [TLB] - G06F 2212/7201: Logical to physical mapping or translation of blocks or pages - G06F 2212/7202: Allocation control and policies - 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 apparatus includes a first storage device and a second storage device, out of logical-physical translation information which associates a logical page and a physical page in the second storage device with each other. Non-compressed logical-physical translation information in the first storage device is assumed to constitute a first tier, compressed logical-physical translation information in the first storage device is assumed to constitute a second tier, and compressed logical-physical translation information in the second storage device is assumed to constitute a third tier. The storage apparatus includes tier management information for managing which logical page is included in logical-physical translation information of which of the first tier, the second tier, and the third tier. When receiving an I/O with respect to the logical page, the storage apparatus retrieves the logical-physical translation information including the logical page for which the I/O has been received, based on the tier management information. ## Claims ### Claim 1 A storage apparatus, comprising: a first storage device; a second storage device; and a controller configured to control the first storage device and the second storage device, in logical-physical translation information which associates logical pages constituting a logical storage area of the second storage device and physical pages constituting a physical storage area of the second storage device with each other, the logical-physical translation information stored in a non-compressed state in the first storage device belongs to a first tier the logical-physical translation information stored in a compressed state in the first storage device belongs to a second tier, and the logical-physical translation information stored in a compressed state in the second storage device belongs to a third tier, the controller being configured to include tier management information for managing which logical page is included in the logical-physical translation information of which of the first tier, the second tier, and the third tier, and the controller being configured to, when receiving an I/O (Input/Output) with respect to a logical page, retrieve the logical-physical translation information including information denoting the logical page for which the I/O has been received, based on the tier management information. ### Claim 2 (depends on 1) The storage apparatus according to claim 1, wherein the second storage device is configured to have a slower I/O rate and a larger storage capacity than the first storage device. ### Claim 3 (depends on 2) The storage apparatus according to claim 2, wherein the controller is configured to, when retrieving logical-physical translation information including information denoting the logical page for which the I/O has been received based on the tier management information, preferentially retrieve logical-physical translation information belonging to the first tier over logical-physical translation information belonging to the second tier, and preferentially retrieve logical-physical translation information belonging to the second tier over logical-physical translation information belonging to the third tier. ### Claim 4 (depends on 2) The storage apparatus according to claim 2, wherein the controller is configured to duplicate logical-physical translation information, out of logical-physical translation information belonging to the third tier, of which an I/O frequency indicating a frequency of I/O to a logical page included in the logical-physical translation information is equal to or higher than a first threshold, to the first storage device in a compressed state, and cause the duplicated logical-physical translation information to belong to the second tier, and decompress logical-physical translation information, out of logical-physical translation information belonging to the second tier, of which the I/O frequency is equal to or higher than a second threshold, which is higher than the first threshold, to bring the logical-physical translation information into a non-compressed state, and cause the logical-physical translation information to belong to the first tier. ### Claim 5 (depends on 4) The storage apparatus according to claim 4, wherein the controller is configured to delete from the second storage device logical-physical translation information, out of logical-physical translation information belonging to the second tier, of which the I/O frequency is lowest, and bring logical-physical translation information, out of logical-physical translation information belonging to the first tier, of which the I/O frequency is lowest into a compressed state, and cause the logical-physical translation information to belong to the second tier. ### Claim 6 (depends on 5) The storage apparatus according to claim 5, wherein the I/O frequency is a value based on access to the logical page from an external apparatus. ### Claim 7 (depends on 2) The storage apparatus according to claim 2, wherein the tier management information includes a storage location in the first storage device, a storage location in the second storage device, and a data size of the logical-physical translation information, relating to the logical-physical translation information, and the data size is a data size in a non-compressed state when the logical-physical translation information belongs to the first tier, and a data size in a compressed state when the logical-physical translation information belongs to the second tier or the third tier. ### Claim 8 (depends on 2) The storage apparatus according to claim 2, wherein the controller is configured to cause logical-physical translation information, of which a priority indicating a degree of priority of the logical-physical translation information is equal to or higher than a first threshold, to belong to the first tier, and cause logical-physical translation information, of which the priority is equal to or higher than a second threshold and lower than the first threshold, to belong to the second tier. ### Claim 9 (depends on 1) The storage apparatus according to claim 1, wherein the second storage device is constituted by a NAND flash memory. ### Claim 10 A storage control method used in a storage apparatus including a first storage device and a second storage device, the method comprising: receiving an I/O with respect to a logical page, and retrieving logical-physical translation information including information denoting the logical page for which the I/O has been received, based on tier management information, in regard to the logical-physical translation information which associates logical pages constituting a logical storage area of the second storage device and physical pages constituting a physical storage area of the second storage device with each other, the logical-physical translation information stored in a non-compressed state in the first storage device to belong to a first tier, the logical-physical translation information stored in a compressed state in the first storage device to belong to a second tier, the logical-physical translation information stored in a compressed state in the second storage device to belong to a third tier, and the tier management information for managing which logical page is included in the logical-physical translation information of which of the first tier, the second tier, and the third tier.