Abstract: A storage system comprises a plurality of storage devices, and is configured to establish a redundant array of independent disks (RAID) arrangement comprising a plurality of stripes, with each of the plurality of stripes comprising a plurality of blocks, the blocks being distributed across multiple ones of the storage devices. In conjunction with establishment of the RAID arrangement, the storage system is further configured, for each of the plurality of stripes, to designate multiple ones of the storage devices as respective spare devices for that stripe, and for each of the storage devices, to determine numbers of the stripes for which that storage device is designated as a spare device for respective ones of the other storage devices in each of multiple spare levels and for each of multiple failure combinations. A particular number of spare blocks is reserved for each of the storage devices using the determined numbers.

Abstract: A storage system comprises mixed-capacity storage devices, including at least one or more storage devices having relatively low capacities and one or more storage devices having relatively high capacities. The storage system is configured to establish a redundant array of independent disks (RAID) arrangement comprising a plurality of stripes, with each of the plurality of stripes comprising a plurality of data blocks and one or more corresponding parity blocks, the data blocks and parity blocks being distributed across multiple ones of the storage devices. In conjunction with establishment of the RAID arrangement, the storage system is further configured to concentrate storage of the parity blocks in the one or more storage devices having the relatively high capacities. The storage devices in some embodiments comprise at least a first set of storage devices each having a first capacity and a second set of storage devices each having a second capacity higher than the first capacity.

Abstract: Embodiments for reducing rebuild time in a computing storage environment in by a processor. One or more disk drive failures in a Redundant Array of Independent Disks (RAID)-6 may be rebuilt by holding at least three parity strips per stripe while using one or more of the at least three parity strips according the one or more disk drive failures.

Abstract: A computer-implemented method according to one embodiment includes identifying a data write to a specific position within a virtual address space, determining an entry within a metadata structure that corresponds to the specific position within the virtual address space, and adding state information associated with the data write to the entry within the metadata structure, the state information including a size of the data write within the virtual address space and an alignment of the data write within the virtual address space.

Abstract: A mechanism is provided in a data processing system comprising at least one processor and at least one memory. The at least one memory comprise instructions which are executed by the at least one processor and configure the processor to implement a read-ahead manager for adaptive read-ahead in log structured storage. The read-ahead manager determines a probability value P representing a probability to read into cache a temporal environment for a front-end read for a given segment in user space in a log structured storage. Responsive to performing a front-end read of a record of the given segment in the log structured storage, the read-ahead manager performs pre-fetch of the temporal environment for the record with probability P.

Abstract: Embodiments for optimizing dual-layered data compression in a storage environment. In a data storage system having a primary compressor implemented in a storage controller and a secondary compressor implemented within a drive-enclosure, the primary compressor is selectively used to perform a first one of a plurality of actions on input/output (I/O) data while a second one of the plurality of actions is performed on the I/O data by the secondary compressor, thereby reducing latency and improving an overall compression performance while processing the I/O data.

Abstract: A computer-implemented method according to one embodiment includes determining resource usage of at least a first module in a grid storage system having multiple modules and approximately equal resource usage across the multiple modules of the grid storage system. The computer-implemented method further includes determining a garbage collection cost in the grid storage system by stopping garbage collection in a second of the modules of the grid storage system, determining a resource usage in the second module upon stopping the garbage collection, and comparing the resource usage in the second module to the resource usage of the at least the first module. The method further includes adjusting an amount of garbage collection based on both the garbage collection cost and the resource usage.

Abstract: A computer-implemented method, according to one embodiment, includes: determining which of a plurality of fingerprints correspond to a copy of user data stored in one or more logical volumes at a storage location, and which of the plurality of fingerprints correspond to a pointer that points to a copy of user data stored in the one or more logical volumes at the storage location. A number of unique fingerprints is determined, and a number of the copies of user data stored in the one or more logical volumes is determined. The number of the copies of user data and the number of unique fingerprints are used to calculate an actual deduplication efficiency value. The number of the copies of user data and the number of unique fingerprints are used to calculate a potential deduplication efficiency value. The actual deduplication efficiency value is compared to the potential deduplication efficiency value.

Abstract: Embodiments for reducing rebuild time in a computing storage environment in by a processor. One or more disk drive failures in a Redundant Array of Independent Disks (RAID)-6 may be rebuilt by holding at least three parity strips per stripe while using one or more of the at least three parity strips according the one or more disk drive failures.

Abstract: Methods that can crypto-erase deduplicated data are disclosed herein. One method includes encrypting, by a processor, each data chunk on a storage device with a unique first encryption key that is different from each other first encryption key and encrypting each storage object on the storage device with a unique second encryption key that is different from each first encryption key and each other second encryption key in which each second encryption key encrypts a first encryption key for a data chunk. Apparatus, systems, and computer program products that can include, perform, and/or implement the methods are also disclosed herein.

Abstract: A computer program product, according to one embodiment, includes a computer readable storage medium having program instructions embodied therewith. The computer readable storage medium is not a transitory signal per se. The program instructions are readable and/or executable by a processor to cause the processor to perform a method which includes: receiving a request to delete a volume stored in one or more regions in physical space of a storage system; determining whether at least one of the regions having at least a portion of the volume includes reclaimable space; deleting the portion of the volume from the at least one region having the reclaimable space in response to determining that at least one of the regions having at least a portion of the volume includes reclaimable space; and failing the received request to delete the volume in response to determining that none of the regions include reclaimable space.

Abstract: A computer-implemented method according to one embodiment includes identifying a data write to a specific position within a virtual address space, determining an entry within a metadata structure that corresponds to the specific position within the virtual address space, and adding state information associated with the data write to the entry within the metadata structure, the state information including a size of the data write within the virtual address space and an alignment of the data write within the virtual address space.

Abstract: Embodiments for optimizing dual-layered data compression in a storage environment. In a data storage system having a primary compressor implemented in a storage controller and a secondary compressor implemented within a drive-enclosure, the primary compressor is selectively used to perform a first one of a plurality of actions on input/output (I/O) data while a second one of the plurality of actions is performed on the I/O data by the secondary compressor, thereby reducing latency and improving an overall compression performance while processing the I/O data.

Abstract: A computer-implemented method according to one embodiment includes determining resource usage of at least a first module in a grid storage system having multiple modules and approximately equal resource usage across the multiple modules of the grid storage system. The computer-implemented method further includes determining a garbage collection cost in the grid storage system by stopping garbage collection in a second of the modules of the grid storage system, determining a resource usage in the second module upon stopping the garbage collection, and comparing the resource usage in the second module to the resource usage of the at least the first module. The method further includes adjusting an amount of garbage collection based on both the garbage collection cost and the resource usage.

Abstract: Methods that can provide distributed data deduplication reference counting are disclosed herein. One method includes generating, by a processor, a secondary reference in response to a determination that a data chunk is a copy of the primary reference in which the primary reference includes a pointer to an existing data chunk stored on a storage device. The method further includes incrementing a secondary reference counter on the primary reference in response to generating the secondary reference. Apparatus and computer program products that can include, perform, and/or implement the methods are also disclosed herein.

Abstract: Embodiments for efficient garbage collection in a data storage environment. In a storage system comprising multiple storage devices having respective sets of storage regions, at least one respective storage fragmentation threshold used to trigger a garbage collection operation is identified. The garbage collection operation is performed to reclaim data space in the storage system according to each of a block perspective and an area perspective. The block perspective performs the garbage collection operation on individual blocks of data and the area perspective performs the garbage collection operation on a plurality of the blocks in a respective storage region. The block perspective and the area perspective portions of the garbage collection operation are executed independently of one another.

Abstract: A computer-implemented method according to one embodiment includes identifying a data write to a specific position within a virtual address space, determining an entry within a metadata structure that corresponds to the specific position within the virtual address space, and adding state information associated with the data write to the entry within the metadata structure, the state information including a size of the data write within the virtual address space and an alignment of the data write within the virtual address space.

Abstract: Embodiments for optimizing dual-layered data compression in a storage environment. In a data storage system having a primary compressor and a secondary compressor, the primary compressor is selectively used to perform a first one of a plurality of actions on Input/Output (I/O) data while a second one of the plurality of actions is performed on the I/O data by the secondary compressor, thereby reducing latency and improving an overall compression performance while processing the I/O data.

Abstract: Links between data regions are intelligently formed, based on up-to-date popularity statistics, including a number of times a particular one of the data regions was a target for a potential link with another one of the data regions. An owner manages a popularity index incorporating the popularity statistics, where over time, the popularity index is subjected to an aging mechanism pursuant to a decaying algorithm. An owner one of the data regions decides whether to accept the one of the intelligently formed links based on at least one of a plurality of predetermined factors. If the one of the intelligently formed links is accepted by the owner one of the data regions, a potential referrer creates one of the data regions using one of the intelligently formed links. If the one of the intelligently formed links is rejected by the owner one of the data regions, data is written.

Abstract: A computer-implemented method, according to one embodiment, includes: determining which of a plurality of fingerprints correspond to a copy of user data stored in one or more logical volumes at a storage location, and which of the plurality of fingerprints correspond to a pointer that points to a copy of user data stored in the one or more logical volumes at the storage location. A number of unique fingerprints is determined, and a number of the copies of user data stored in the one or more logical volumes is determined. The number of the copies of user data and the number of unique fingerprints are used to calculate an actual deduplication efficiency value. The number of the copies of user data and the number of unique fingerprints are used to calculate a potential deduplication efficiency value. The actual deduplication efficiency value is compared to the potential deduplication efficiency value.