# US 2016/0259588 A1 · Efficient rebuild of storage devices in a redundant array of independent disks (raid) > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2016/0259588 A1 - Document ID: US20160259588A1 - Status: Published application - Kind: A1 - Application number: 14/640,157 - Filed: 2015-03-06 - Published: 2016-09-08 - Earliest claimed: 2015-03-06 - Assignees: Dell Products L.P. - Applicants: Dell Products L.P. - Inventors: Ashokan Vellimalai; Deepu Syam Sreedhar M; Sandeep Agarwal; Anup Atluri - Web page: https://patentgrep.com/patent/US20160259588A1 ## CPC - G06F 3/0634: {by changing the state or mode of one or more devices} - G06F 3/0605: {by facilitating the interaction with a user or administrator} - G06F 3/0607: {by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device} - G06F 3/0617: {in relation to availability} - G06F 3/0632: {by initialisation or re-initialisation of storage systems} - G06F 3/0689: {Disk arrays, e.g. RAID, JBOD} - G06F 11/00: Error detection; Error correction; Monitoring (error detection, correction or monitoring in information storage based on relative movement between record carrier and transducer G11B20/18; monitoring, i.e. supervising the progress of recording or reproducing G11B27/36; in static stores G11C29/00) - G06F 11/1092: {Rebuilding, e.g. when physically replacing a failing disk} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract Methods and systems for efficient rebuild of storage devices in a RAID may include generating a data-modified map of a storage device. The data-modified map may be updated when a RAID virtual device associated with the storage device is degraded to indicate write operations. The data-modified map may be used to rebuild selective portions of the storage device, instead of performing a full rebuild. The data-modified map may also be used to perform a full rebuild of the storage device. ## Claims ### Claim 1 A method comprising: detecting a storage device added to a redundant array of independent disks (RAID) storage array controlled by a RAID controller; determining whether the storage device was previously used in the RAID storage array; and when the storage device was previously used in the RAID storage array: identifying a data-modified map previously generated for the storage device, the data-modified map indicating modified portions of the storage device; and based on the data-modified map, rebuilding the modified portions of the storage device. ### Claim 2 (depends on 1) The method of claim 1, further comprising: when the storage device was not previously used in the RAID storage array: generating the data-modified map for the storage device; setting the data-modified map to indicate full rebuild of the storage device, wherein all portions of the storage device are indicated as modified portions in the data-modified map; and based on the data-modified map, rebuilding the modified portions of the storage device. ### Claim 3 (depends on 1) The method of claim 1, wherein generating the data-modified map includes: generating a plurality of stripe maps respectively associated with RAID stripe sets used in the storage device, wherein each of the stripe maps includes a plurality of stripe units corresponding in number to a number of the RAID stripe sets; generating a leaf array corresponding to the plurality of stripe maps, wherein each element in the leaf array indicates a change in a respective stripe map; generating an upper level array corresponding to at least some elements in a lower level array selected from the leaf array and a different upper level array, wherein each element in the upper level array indicates a change in elements of the lower level array; and generating a top level array having one element, the element in the top level array indicating a change in the storage device. ### Claim 4 (depends on 2) The method of claim 2, further comprising, after the activating of the storage device in the RAID storage array: determining whether a RAID virtual device associated with the storage device was degraded, wherein a degraded RAID virtual device does not have access to at least one RAID stripe set; and when the RAID virtual device is degraded, updating the data-modified map in response to receiving a write instruction for the RAID virtual device, wherein the data-modified map is updated based on the write instruction. ### Claim 5 (depends on 1) The method of claim 1, wherein the storage device is selected from a rotating-media storage device and a solid state storage device. ### Claim 6 (depends on 1) The method of claim 1, wherein the identifying the data-modified map includes identifying the data-modified map in a memory accessible to the RAID controller. ### Claim 7 (depends on 1) The method of claim 1, wherein the RAID controller controls a plurality of storage devices, including the storage device, and further comprising: generating a plurality of data-modified maps respectively corresponding to the plurality of storage devices. ### Claim 8 An information handling system, comprising a redundant array of independent disks (RAID) controller, the RAID controller further comprising: a non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to: detect a storage device added to a RAID storage array controlled by the RAID controller; determine whether the storage device was previously used in the RAID storage array; when the storage device was previously used in the RAID storage array, identify a data-modified map previously generated for the storage device, the data-modified map indicating modified portions of the storage device; and when the storage device was not previously used in the RAID storage array: generate the data-modified map for the storage device; and set the data-modified map to indicate full rebuild of the storage device, wherein all portions of the storage device are indicated as modified portions in the data-modified map; and based on the data-modified map, rebuild the modified portions of the storage device. ### Claim 9 (depends on 8) The information handling system of claim 8, wherein the instructions to generate the data-modified map include instructions to: generate a plurality of stripe maps respectively associated with RAID stripe sets used in the storage device, wherein each of the stripe maps includes a plurality of stripe units corresponding in number to a number of the RAID stripe sets; generate a leaf array corresponding to the plurality of stripe maps, wherein each element in the leaf array indicates a change in a respective stripe map; generate an upper level array corresponding to at least some elements in a lower level array selected from the leaf array and a different upper level array, wherein each element in the upper level array indicates a change in elements of the lower level array; and generate a top level array having one element, the element in the top level array indicating a change in the storage device. ### Claim 10 (depends on 8) The information handling system of claim 8, further comprising instructions to, after activation of the storage device in the RAID storage array: determine whether a RAID virtual device associated with the storage device was degraded, wherein a degraded RAID virtual device does not have access to at least one RAID stripe set; and when the RAID virtual device is degraded, update the data-modified map in response to receiving a write instruction for the RAID virtual device, wherein the data-modified map is updated based on the write instruction. ### Claim 11 (depends on 8) The information handling system of claim 8, wherein the storage device is selected from a rotating-media storage device and a solid state storage device. ### Claim 12 (depends on 8) The information handling system of claim 8, wherein the instructions to identify the data-modified map include instructions to identify the data-modified map in a memory accessible to the RAID controller. ### Claim 13 (depends on 8) The information handling system of claim 8, wherein the RAID controller controls a plurality of storage devices, including the storage device, and further comprising instructions to: generate a plurality of data-modified maps respectively corresponding to the plurality of storage devices. ### Claim 14 A redundant array of independent disks (RAID) controller comprising: a non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to: detect a storage device added to a RAID storage array controlled by the RAID controller; determine whether the storage device was previously used in the RAID storage array; and when the storage device was previously used in the RAID storage array: identify a data-modified map previously generated for the storage device, the data-modified map indicating modified portions of the storage device; and based on the data-modified map, rebuild the modified portions of the storage device. ### Claim 15 (depends on 14) The RAID controller of claim 14, further comprising instructions to: when the storage device was not previously used in the RAID storage array: generate the data-modified map for the storage device; set the data-modified map to indicate full rebuild of the storage device, wherein all portions of the storage device are indicated as modified portions in the data-modified map; and based on the data-modified map, rebuild the modified portions of the storage device. ### Claim 16 (depends on 15) The RAID controller of claim 15, wherein the instructions to generate the data-modified map include instructions to: generate a plurality of stripe maps respectively associated with RAID stripe sets used in the storage device, wherein each of the stripe maps includes a plurality of stripe units corresponding in number to a number of the RAID stripe sets; generate a leaf array corresponding to the plurality of stripe maps, wherein each element in the leaf array indicates a change in a respective stripe map; generate an upper level array corresponding to at least some elements in a lower level array selected from the leaf array and a different upper level array, wherein each element in the upper level array indicates a change in elements of the lower level array; and generate a top level array having one element, the element in the top level array indicating a change in the storage device. ### Claim 17 (depends on 15) The RAID controller of claim 15, further comprising instructions to, after activation of the storage device in the RAID storage array: determine whether a RAID virtual device associated with the storage device was degraded, wherein a degraded RAID virtual device does not have access to at least one RAID stripe set; and when the RAID virtual device is degraded, update the data-modified map in response to receiving a write instruction for the RAID virtual device, wherein the data-modified map is updated based on the write instruction. ### Claim 18 (depends on 14) The RAID controller of claim 14, wherein the storage device is selected from a rotating-media storage device and a solid state storage device. ### Claim 19 (depends on 14) The RAID controller of claim 14, wherein the instructions to identify the data-modified map include instructions to identify the data-modified map in a memory accessible to the RAID controller. ### Claim 20 (depends on 14) The RAID controller of claim 14, wherein the RAID controller controls a plurality of storage devices, including the storage device, and further comprising instructions to: generate a plurality of data-modified maps respectively corresponding to the plurality of storage devices.