Abstract: Embodiments include a method performed by a computing device. The method includes (a) receiving a plurality of access requests to access data of a multilayered storage system; (b) in response to determining that a first access request can be served from a top data layer, executing the first access request by accessing the top data layer; (c) in response to determining that a second access request cannot be served from the top data layer, determining whether a current concurrency number of the top data layer is less than a permitted concurrency number (PCN) of the top data layer; and (d) in response to determining that the current concurrency number of the top data layer is not less than the PCN, waiting until the current concurrency number of the top data layer is less than the PCN and then executing the second access request by accessing another data layer below the top layer.

Abstract: Implementations of the subject matter described herein provide a storage management method and system. The storage management method comprises: in response to receiving a write request, dividing data to be written into a plurality of data blocks with a predetermined size, the plurality of data blocks having their respective logic block addresses; evenly mapping, based on the logic block addresses, the plurality of data blocks to a plurality of RAID extents of a Redundant Array of Independent Disks (RAID); mapping the plurality of data blocks in the plurality of RAID extents to the disk, so that the plurality of data blocks are distributed in order of size of logic block addresses in the disk.

Abstract: Embodiments of the present disclosure relate to methods and apparatuses for data copy. A method comprises receiving, from a client module in a first processing unit, a read request for reading data from a first storage region. The method further comprises, in response to determining from the read request that the data is to be copied, obtaining, from a cache, a first bitmap associated with the first storage region, the first bitmap indicating if the first storage region is filled with zero. The method further comprises, in response to determining from the first bitmap that the first storage region is filled with zero, sending, to the client module, an indication that the data is zero.

Abstract: A storage method and device for a solid-state drive is provided in embodiments of the present disclosure. The method includes: configuring a checkpoint drive and a cache drive; backing up data blocks from a data drive into the checkpoint drive; and in response to the data drives being corrupted, writing into a further data drive part of the data blocks backed up into the checkpoint drive and part of data blocks in the cache drive. The number of required SSD drives can be significantly reduced with the method and device without losing the data restoration capability. In addition, the degrading performance can also be maintained at a relatively high level.

Abstract: A method, computer program product, and computer system for receiving, by a computing device, an I/O request, wherein the I/O request may include host I/O priority information. It may be determined that the I/O request is associated with a token bucket of a plurality of token buckets based upon, at least in part, the host I/O priority information. If the token bucket of the plurality of token buckets has sufficient tokens for the I/O request, the I/O request may be sent down a block stack for processing, and if the token bucket of the plurality of token buckets has insufficient tokens for the I/O request, the I/O request may be rejected.

Abstract: Various embodiments of the present disclosure generally relate to a fault processing method, system and computer program product. Specifically, the method may comprise determining a plurality of devices to be detected and corresponding device attributes. The method may also comprise performing a first fault detection for the plurality of devices based on the device attributes, the first fault detection being based on a first fault diagnosis rule that is generic for the plurality of devices. Besides, the method may also comprise: in response to a first device in the plurality of devices being determined to have a fault in the first fault detection, performing a first fault processing to the first device, the first fault processing being based on a first fault processing rule that is generic for the plurality of devices.

Abstract: While migrating a source volume to a destination storage array, disabling the source volume causes a source storage array to send a non-standard failure status code to all host computers in a cluster that includes the source storage array and the destination storage array. While the source volume is disabled with regard to standard host I/O requests received from host computers in the cluster, in response to receipt of the non-standard failure status code, a customized plugin added to the host computers transfers persistent reservation information to the destination storage array using non-standard read and set persistent reservation information commands. The destination volume is then enabled to process host I/O requests in accordance with the transferred persistent reservation information, and an active path for accessing the source volume is modified in each one of the host computers in the cluster to indicate the destination volume in the destination storage array.

Abstract: A storage method and device for a solid-state drive is provided in embodiments of the present disclosure. The method includes: configuring a checkpoint drive and a cache drive; backing up data blocks from a data drive into the checkpoint drive; and in response to the data drives being corrupted, writing into a further data drive part of the data blocks backed up into the checkpoint drive and part of data blocks in the cache drive. The number of required SSD drives can be significantly reduced with the method and device without losing the data restoration capability. In addition, the degrading performance can also be maintained at a relatively high level.

Abstract: The present disclosure relates to an apparatus for a data storage device, an adapter, an array controller, a data storage device, and a relevant method. The apparatus for the data storage device comprises: a power management module configured to detect power-off of a power supply and to switch to a backup battery unit in the data storage device in response to detecting the power supply. The apparatus is configured to cause the backup battery unit to supply power only to the volatile memory in the data storage device. By using a solution according to the present disclosure, for example, preserving time for data may be prolonged in the case of power-off.

Abstract: The present disclosure provides a method and apparatus for online reducing cache devices from a cache. The cache includes a first cache device and a second cache device, the method comprising: keeping the cache and the second cache device in an enabled state; labeling the first cache device as a to-be-reduced device so as to block a new data page from being promoted to the first cache device; removing a cached data page from the first cache device; removing the cached input output (IO) historical information from the first cache device; and removing the first cache device from the cache. There is also provided a corresponding apparatus.

Abstract: Embodiments of the present disclosure relate to a method and apparatus for facilitating wear leveling of a solid state disk (SSD). The method comprises obtaining a performance parameter of a SSD device of a plurality of SSD devices in the SSD cache, and the SSD device includes one or more SSD disks. The method further comprises determining a weight for the SSD device based on the performance parameter of the SSD device. The method also comprises setting reserved space for the SSD device according to the weight for the SSD device, and the reserved space is inaccessible in the SSD device.

Abstract: Embodiments of the present disclosure relate to methods, devices and computer program products for writing data in a disk array in a storage system. The storage system comprises a disk array. The method comprises: in response to receiving a write request to write new data to a data block in at least one disk array group in a degraded mode within a disk array, reading old data stored in the data block and old parity information stored in a parity block associated with the data block. The method further comprises: determining new parity information associated with the new data based on the old data, the old parity information and the new data. The method further comprises: writing the new data and the new parity information into at least one cache page provided by a cache component in the storage system, the at least one cache page being allocated in a persistent memory in the cache component.

Abstract: Embodiments of the present disclosure relate to methods, devices and computer program products for managing a redundant array of independent disks (RAID). The method comprises: in response to a number of a plurality of disks occupied by the RAID exceeding a first threshold, determining a first number of disk pairs to be disassociated among the plurality of disks, the first number of disk pairs at least comprising a first disk and a second disk associated with each other, and a first extent in the first disk and a second extent in the second disk being included in a same RAID extent of the RAID. The method further comprises determining a third disk for migrating at least one of the first extent and the second extent among the plurality of disks. Besides, the method further comprises migrating the at least one extent to the third disk to disassociate the first disk and the second disk so that a second number of disk pairs associated with each other among the plurality of disks is below a second threshold.

Abstract: Embodiments of the present disclosure provide a method, device and computer program product for cache management. The method includes: receiving from a storage device an indication for an invalid storage block in the storage device; in response to receiving the indication, looking up a cache page associated with the invalid storage block in the cache; in response to finding the cache page in the cache, determining validity of data in the cache page; and in response to the data being invalid, reclaiming the cache page.

Abstract: A method, computer program product, and computer system for receiving, by a computing device, an I/O request, wherein the I/O request may include host I/O priority information. It may be determined that the I/O request is associated with a token bucket of a plurality of token buckets based upon, at least in part, the host I/O priority information. If the token bucket of the plurality of token buckets has sufficient tokens for the I/O request, the I/O request may be sent down a block stack for processing, and if the token bucket of the plurality of token buckets has insufficient tokens for the I/O request, the I/O request may be rejected.

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 method and device for managing a storage system comprising multiple storage devices in a first layer and at least one backup storage device in a second layer. In response to receiving a request for writing target data to the storage system, storing the target data to a first portion of storage devices among the multiple storage devices in the first layer; storing a first parity, determined on the basis of a first algorithm, of data in the first portion of storage devices to a second portion of storage devices among the multiple storage devices in the first layer; and storing a second parity, determined on the basis of a second algorithm, of data in the first portion of storage devices to a first backup storage device of the at least one backup storage device in the second layer.

Abstract: There is provided a method and apparatus of expanding capacity for a cache array. The method includes in response to detecting that a first new cache disk is to be added to a first cache array, initializing the first new cache disk without disabling other cache disks in the first cache array; allocating a storage space for a cache page metadata based on a result of the initializing; storing the cache page metadata into an initialized directory logical unit number, DIR LUN; storing a copy of the cache page metadata from a memory into the DIR LUN to facilitate the first cache disk to be in a ready state; and in response to the first new cache disk being in the ready state, configuring the first new cache disk as being in an initialized state to expand the capacity of the first cache array.

Abstract: Implementations of the subject matter described herein provide a storage management method and system. The storage management method comprises: in response to receiving a write request, dividing data to be written into a plurality of data blocks with a predetermined size, the plurality of data blocks having their respective logic block addresses; evenly mapping, based on the logic block addresses, the plurality of data blocks to a plurality of RAID extents of a Redundant Array of Independent Disks (RAID); mapping the plurality of data blocks in the plurality of RAID extents to the disk, so that the plurality of data blocks are distributed in order of size of logic block addresses in the disk.

Abstract: Embodiments of the present disclosure relate to a method and a device for cache management. The method includes: in response to receiving a write request for a cache logic unit, determining whether a first cache space of a plurality of cache spaces associated with the cache logic unit is locked; in response to the first cache space being locked, obtaining a second cache space from the plurality of cache spaces, the second cache space being different from the first cache space and being in an unlocked state; and performing, in the second cache space, the write request for the cache logic unit.