Abstract: Technology for determining an effective capacity of a drive extent pool that is generated from at least one group of storage drives. A sub-group of storage drives having relatively higher physical capacities is selected from the group. The number of storage drives in the sub-group is equal to a total number of drive extents indicated by each entry in a RAID mapping table. Each storage drive in the sub-group is assigned an individual effective capacity equal to an individual physical capacity of a storage drive in the sub-group having the smallest individual physical capacity. Each storage drive in the group not contained in the sub-group is assigned an individual effective capacity equal to its own physical capacity. An effective capacity of the drive extent pool is set to a sum of the all the individual effective capacities assigned to the storage drives in the group of storage drives.

Abstract: A method, computer program product, and computer system for initializing, on a computing device, an N*N Weighted Neighborhood Matrix according to an existing Mapped RAID layout. N disks in an original disk partner group (DPG) may be partitioned into a target DPG, where N is a number of disks in an extent pool, wherein the N disks have at least two different capacities. The target DPG may be marked for at least a portion of the N disks. The target DPG may be marked for E RAID extents, where E is a number of RAID extents in the original DPG. At least a portion of disk extents for the E RAID extents in the original DPG may be moved to the target DPG.

Abstract: A method, computer program product, and computer system for selecting, by a computing device, a first disk extent for each RAID extent in an extent pool. Remaining disk extents for each RAID extent in the extent pool may be selected.

Abstract: A method, computer program product, and computer system for receiving, by a computing device, an I/O request for data. A number of storage devices of a plurality of storage devices in a Mapped RAID group that will be used to process the I/O request may be determined. It may be determined that an amount of I/O credits available for the number of storage devices is insufficient. The amount of I/O credits available for the number of storage devices to process the I/O request may be tuned dynamically based upon, at least in part, determining that the amount of I/O credits available for the number of storage devices is insufficient.

Abstract: Mapped RAID (Redundant Array of Independent Disks) technology divides individual drives into multiple drive extents, allocates the drive extents to RAID extent entries in a RAID mapping table, and performs “end of life” detection and proactive copying of data between data storage drives on a per drive extent basis. A given drive extent is determined to be “end of life” when the ratio of soft media errors to total I/O operations for the drive extent exceeds a threshold error ratio. Data stored on the drive extent is then proactively copied to a newly allocated drive extent, the RAID mapping table is modified so that the data is subsequently accessed from the newly allocated drive extent, and the drive extent is excluded from being used again to store host data. As a result, the rate at which the drives experience soft media errors is slowed, lengthening their effective life.

Abstract: Techniques are disclosed for managing data storage. In one embodiment, the techniques determine one or more RAID extents having a disk extent supported by an extent of storage on a storage device in an inoperative state. Each of the RAID extents contains a respective set of disk extents allocated to that RAID extent and each disk extent is supported by an extent of storage on a storage device of the set of storage devices. The techniques also comprise evaluating a set of values, wherein each value indicates, for a corresponding pair of storage devices from the set of storage devices, a number of RAID extents which contain disk extents belonging to both storage devices of the pair.

Abstract: Technology for determining an effective capacity of a drive extent pool that is generated from at least one group of storage drives. A sub-group of storage drives having relatively higher physical capacities is selected from the group. The number of storage drives in the sub-group is equal to a total number of drive extents indicated by each entry in a RAID mapping table. Each storage drive in the sub-group is assigned an individual effective capacity equal to an individual physical capacity of a storage drive in the sub-group having the smallest individual physical capacity. Each storage drive in the group not contained in the sub-group is assigned an individual effective capacity equal to its own physical capacity. An effective capacity of the drive extent pool is set to a sum of the all the individual effective capacities assigned to the storage drives in the group of storage drives.

Abstract: A mapped RAID system that reduces drive extent allocation changes when splitting a group of storage drives into a first partnership group and a second partnership group. A first drive is assigned to the first partnership group, and then additional drives are assigned to the first partnership group from the unassigned drives, such that each drive assigned to the first partnership group has a lowest movement count of all unassigned drives. A drive's movement count represents a count of drive extent allocations that must be changed if the drive is added to the first partnership group. After each drive is assigned to the first partnership group, the indication of the drive is removed from the list of unassigned drives. A group of RAID extent entries for the first partnership group consists of RAID extent entries indicating relatively higher total numbers of drive extents located in the first partnership group.

Abstract: Technology for relocating data stored in an end of life source storage drive that identifies individual destination drive extents corresponding to drive extents located in the source storage drive by selecting individual storage drives within a set of healthy storage drives in a group of storage drives in a round robin manner and identifying an individual destination drive extent from each selected storage drive. The corresponding destination drive extents replace the drive extents located in the source storage drive, and are used to store data copied from the drive extents located in the source storage drive. Data is copied in parallel from a set of multiple drive extents located in the source storage drive that is selected based on the current total input/output load determined for each storage drive in the set of healthy storage drives, and on the storage drives on which the corresponding destination drive extents are located.

Abstract: Mapped RAID (Redundant Array of Independent Disks) technology divides individual drives into multiple drive extents, allocates the drive extents to RAID extent entries in a RAID mapping table, and performs “end of life” detection and proactive copying of data between data storage drives on a per drive extent basis. A given drive extent is determined to be “end of life” when the ratio of soft media errors to total I/O operations for the drive extent exceeds a threshold error ratio. Data stored on the drive extent is then proactively copied to a newly allocated drive extent, the RAID mapping table is modified so that the data is subsequently accessed from the newly allocated drive extent, and the drive extent is excluded from being used again to store host data. As a result, the rate at which the drives experience soft media errors is slowed, lengthening their effective life.

Abstract: Implementations of the present disclosure relate to a method, system and computer program product for managing a storage system. Specifically, in one implementation of the present disclosure there is provided a method for managing a storage system. The method comprises: determining an access level of a target extent comprised in a stripe of a storage system, the access level indicating the possibility that the target extent will be accessed; obtaining a usage state of a target storage device where the target extent resides, the target storage device residing in a storage device pool associated with the storage system; and processing a mapping relationship between the target extent and the target storage device on the basis of the access level and the usage state. In other implementations of the present disclosure, there is provided a corresponding system and computer program product.

Abstract: Embodiments of the present disclosure relate to a method, device and computer program product for managing a disk array. The method comprises determining respective degrees of wear for a plurality of disks in the disk array, each of the plurality of disks comprising a plurality of disk extents, and each disk extent comprising a plurality of blocks. The method further comprises determining respective numbers of blocks that are accumulatively written into the plurality of disks during a predetermined period of time. The method further comprises migrating data among the plurality of disks based on the degrees of wear and the number of the accumulatively written blocks.

Abstract: Implementations of the present disclosure relate to a method, system and computer program product for managing a storage system. Specifically, in one implementation of the present disclosure there is provided a method for managing a storage system. The method comprises: dividing a source device among a plurality of storage devices in the storage system into a plurality of extents; copying data in the plurality of extents to a destination device; determining the state of an extent among the plurality of extents on the basis whether data in the extent among the plurality of extents has been copied to the destination device; and managing an access request to the extent on the basis of the state of the extent. In other implementations of the present disclosure, there is provided a corresponding system and computer program product.

Abstract: Implementations of the present disclosure relate to a method, system and computer program product for managing a storage system. Specifically, in one implementation of the present disclosure there is provided a method for managing a storage system. The storage system comprises at least one stripe, a stripe of the at least one stripe comprising multiple extents among which respective extents being from respective storage devices in a resource pool. The method comprises: in response to receiving a converting request to convert the storage system from a first type to a second type, determining a target storage device associated with the converting request in the resource pool; for a stripe of the at least one stripe, updating metadata associated with the stripe so as to remove from the stripe an extent that is located at the target storage device; and converting the storage system from the first type to the second type on the basis of the updated metadata.

Abstract: Embodiments of the present disclosure relate to a method, a device and a computer program product for managing a storage system. According to embodiments of the present disclosure, the method comprises, in response to a certain disk of a disk array of the storage system returning from a failed state to a normal state, determining information of a spare disk for recovering data on the storage disk, the first data being stored on the first disk. The method further comprises determining based at least in part on information of the spare disk, a disk from the spare disk and a first disk for reconstructing the disk array. According to embodiments of the present disclosure, in the case that the first disk is recovered from the failed state, the method comprises based on a data amount in the spare disk having not been recovered yet and a data amount associated with the first disk, selecting the spare disk or the first disk for data reconstruction.

Abstract: A mapped RAID group is generated that contains multiple RAID extents, and each one of the RAID extents is configured and arranged to indicate multiple drive extents that are each a contiguous region of non-volatile data storage in a physical drive. The RAID extents are divided into equal size subsets based on a requested RAID width. Drive extents are allocated from a drive extent pool such that the drive extents indicated by RAID extents contained in the same subset are all allocated from different ones of the physical drives. Logical block rotation is performed between the storage object and the mapped RAID group, causing host data written to consecutive blocks of the storage object address space to be directed to different ones of the RAID extents in the mapped RAID group. Data mirroring is performed between drive extents contained within each of the individual RAID extents of the RAID group.

Abstract: A method performed in a Mapped RAID system includes: (a) in response to a source disk (SD) reaching EOL status: (1) copying a first source disk extent (DE) (belonging to a first RAID extent) from the SD to a first spare DE on a first destination disk and (2) copying a second source DE from the SD to a second spare DE (belonging to a second RAID extent) on a second destination disk, (b) in response to completely copying the first source DE from the SD to the first spare DE, mapping the first spare DE to belong to the first RAID extent in place of the first source DE, and (c) in response to completely copying the second source DE from the SD to the second spare DE, mapping the second spare DE to belong to the second RAID extent in place of the second source DE.

Abstract: Techniques are disclosed which monitor the distribution of I/O activity across the storage drives of a data storage system and detect non-uniform distributions of I/O operations across the storage drives by monitoring I/O operations directed to disk extents supporting mapped RAID extents. In response to detecting non-uniform distributions of I/O operations across the storage drives, these techniques identify LUNs with non-uniform I/O patterns and redistribute data stored in those LUNs across RAID extents supporting those LUNs.

Abstract: Technology is provided within a mapped RAID (Redundant Array of Independent Disks) system for creating multiple storage sub-groups in a group of disk drives. Each one of the storage sub-groups contains, in each one of the hard disk drives in the group of hard disk drives, a contiguous set of blocks of storage located within a unique range of logical block addresses corresponding to the storage sub-group. Based on the storage sub-groups created by the disclosed technology, a unique corresponding set of drive extents is allocated to each one of the RAID extents in the RAID mapping table, such that all drive extents contained in each one of the sets of drive extents are allocated from within a single one of the storage sub-groups. Drive extents may be allocated such that a low level of variance is maintained within values of a neighborhood matrix for the group of disk drives.

Abstract: Technology is provided within a mapped RAID system that creates multiple RAID extent sub-groups in a RAID mapping table. Each of the RAID extent sub-groups contains a unique set of consecutively located RAID extents within the RAID mapping table, and a unique corresponding set of drive extents is allocated to the RAID extents contained in each one of the RAID extent sub-groups. Drive extents are allocated to each RAID extent sub-group such that no drive extent is allocated to any RAID extent contained in the RAID extent sub-group that is located on the same hard disk drive as any other drive extent allocated to any other RAID extent contained in that RAID extent sub-group. Data striping may be performed based on the RAID extent sub-groups, such that host data is divided into data elements that are striped across the RAID extents contained in one or more individual RAID extent sub-groups.