Abstract: A method of initializing a data storage system (DSS) is provided. The method includes (a) in response to the DSS booting, reading data from a first plurality of disks marked as part of a raw mirror which mirrors configuration data of the DSS between the first plurality of disks; (b) comparing sequence numbers from the read data read and selecting data from a disk of the first plurality having a latest sequence number; (c) obtaining configuration data of the DSS from the selected data; (d) using the configuration data to construct a topology of the DSS which includes information describing a relationship between a second plurality of disks of the DSS, RAID groups of the DSS, and logical disks presented to users, the second plurality of disks being larger than and including the first plurality of disks; and (e) initializing the RAID groups and the logical disks described by the topology based on the information of the topology.

Abstract: A method and system for managing a storage system, the method comprising: creating a storage system including a first number of stripes, wherein each of the first number of stripes includes a second number of extents, and each of the second number of extents is distributed over a different storage device in a group of storage devices; with respect to a stripe among the first number of stripes, generating stripe information descriptive of a mapping relation between the second number of extents included in the stripe and the different storage devices in the group of storage devices; and with respect to a storage device where an extent among the second number of extents is located, building extent information about a mapping relation between an extent in the storage device and the stripe. In one embodiment of the present invention, there is provided a corresponding device and system.

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: Techniques perform I/O management. The techniques involve: in response to receiving an I/O request for a redundant array of independent disks (RAID), placing the I/O request in a corresponding waiting queue based on a stripe related to the I/O request in the RAID; and in response to the I/O request being granted to process, executing the I/O request based on storage of data of the stripe in a cache memory. Accordingly, by using the cache mechanism for the stripes, the I/O processing efficiency is improved and the user experience is enhanced. Moreover, the count of access to the RAID is reduced, the bandwidth for the backend access is saved and the system performance is improved.

Abstract: Embodiments of the present disclosure provide a method of storage allocation, an electronic device, a storage system and a computer program product. The method of storage allocation includes: obtaining respective wear levels of a plurality of disks associated with a redundant array of independent disks (RAID). The method further includes: determining respective spare extents in disk extents of the plurality of disks based on the obtained wear levels, such that a number of spare extents in a disk is positively correlated with the wear level of the disk. The method also includes: selecting, from disk extents other than the spare extents, a predetermined number of disk extents for creating RAID extents for the RAID, the predetermined number of disk extents being from different disks of the plurality of disks. Through the embodiments of the present disclosure, a life cycle of a disk is prolonged, frequent replacement of worn disks with new disks is avoided, and data loss is reduced.

Abstract: In response to detecting that a total number of physical data storage drives in a group of physical data storage drives exceeds a maximum drive group size, the group of physical data storage drives is divided into a multiple partnership groups, and RAID extents in a RAID mapping table are divided into multiple RAID extent groups. Each one of the RAID extent groups contains multiple RAID extents and corresponds to one of the partnership groups of physical data storage drives. The RAID extents in each RAID extent group only indicate physical data storage drives contained in the corresponding partnership group of physical data storage drives, in order to ensure that data recovery and RAID extent rebuilding after a drive failure involve only the physical data storage drives within the same partnership group as the failed physical data storage drive.

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: The present disclosure provides a storage management method, a device and a computer-readable medium. The method comprises: receiving a request for creating a storage space, the request at least comprising a storage capacity and a RAID configuration of the storage space, the RAID configuration at least indicating a RAID type; allocating an extent based on the storage capacity; creating a RAID group for the extent based on the RAID type; and storing metadata of the RAID group in the extent, the metadata indicating a configuration of the RAID group and a configuration of a user data region in the extent.

Abstract: a method and an apparatus for maintaining reliability of a mapped redundant array of independent disks. The method comprises: determining a first data loss probability, the first data loss probability indicating reliability of a traditional redundant array of independent disks; determining a second data loss probability, the second data loss probability indicating reliability of the mapped redundant array of independent disks; and determining, based on the first and second data loss probabilities, a condition for maintaining the reliability of the mapped redundant array of independent disks. Compared with the prior art, embodiments of the present disclosure can effectively predict the reliability of a mapped RAID through comparison with a traditional RAID, so as to be capable of determining a reliability relationship between the traditional RAID and the mapped RAID. In this way, the reliability of the traditional RAID will not be degraded when being expanded into the mapped RAID.

Abstract: Embodiments of the present disclosure provide a method of managing a redundant array of independent disks (RAID) system and an electronic device. The method includes configuring a plurality of disks in the RAID system as a raw mirror for storing configuration data of the RAID system; storing metadata for the raw mirror in the plurality of disks, the metadata stored in each of the plurality disks including an identifier identifying that the disk belongs to the raw mirror and a sequence number identifying a writing operation for a block storing the metadata in the disk; and controlling reading and writing of the raw mirror based on the metadata.

Abstract: Techniques manage data of a Redundant Array of Independent Disks (RAID). Such techniques involve: obtaining a first parity of checksum pair, which is determined based on a first checksum when user data of data disks in the RAID are predetermined values; determining, based on current checksums of the data disks in the RAID, a second parity of checksum pair of the RAID, the first parity of checksum pair and the second parity of checksum pair respectively comprising a row parity of checksum and a diagonal parity of checksum; and determining, based on the first parity of checksum pair and the second parity of checksum pair, a third parity of checksum pair for updating parity data of parity disks of the RAID.

Abstract: Techniques rebuild data in a storage array group. Such techniques involve: in response to determining that a first storage device of a plurality of storage devices comprised in the storage array group is in a non-working state, generating a write record of the first storage device, the write record indicating whether a write operation occurs for each of a plurality of storage areas in the first storage device during the non-working state; in response to determining that the first storage device returns from the non-working state to a working state, determining, based on the write record, whether a target storage area in need of execution of data rebuilding is present in the first storage device; and controlling, based on the determining, the data rebuilding to be executed on the target storage area.

Abstract: Techniques manage a redundant array of independent disks. The techniques involve: in response to receiving a first command for assigning a first RAID stripe to a RAID group, storing metadata information of the first RAID stripe in a cache, the cache having different input/output (I/O) performance from the RAID; and storing the first command and the metadata information of the first RAID stripe in a predetermined storage space of the RAID in a sequential storage structure.

Abstract: Techniques involve: detecting whether a first set of disks include an inaccessible disk, respective disk sections in the first set of disks forming a first set of stripes; in response to detecting the first set of disks including the inaccessible disk, determining faulty stripes in the first set of stripes, the faulty stripes including a first number of inaccessible disk sections; and in response to the first number exceeding a second number of free sections of the first set of disks, moving data in at least one stripe in the first set of stripes to free sections of the second set of disks to release sections of the at least one stripe, respective disk sections in the second set of disks forming a second set of stripes, each stripe in the first set of stripes and the second set of stripes having the same number of sections.

Abstract: Embodiments of the present disclosure provide a method of storage allocation, an electronic device, a storage system and a computer program product. The method of storage allocation includes: obtaining respective wear levels of a plurality of disks associated with a redundant array of independent disks (RAID). The method further includes: determining respective spare extents in disk extents of the plurality of disks based on the obtained wear levels, such that a number of spare extents in a disk is positively correlated with the wear level of the disk. The method also includes: selecting, from disk extents other than the spare extents, a predetermined number of disk extents for creating RAID extents for the RAID, the predetermined number of disk extents being from different disks of the plurality of disks. Through the embodiments of the present disclosure, a life cycle of a disk is prolonged, frequent replacement of worn disks with new disks is avoided, and data loss is reduced.

Abstract: A method and system for managing a storage system, the method comprising: creating a storage system including a first number of stripes, wherein each of the first number of stripes includes a second number of extents, and each of the second number of extents is distributed over a different storage device in a group of storage devices; with respect to a stripe among the first number of stripes, generating stripe information descriptive of a mapping relation between the second number of extents included in the stripe and the different storage devices in the group of storage devices; and with respect to a storage device where an extent among the second number of extents is located, building extent information about a mapping relation between an extent in the storage device and the stripe. In one embodiment of the present invention, there is provided a corresponding device and system.

Abstract: A method, computer program product, and computer system for adding, by a computing device, a plurality of disks in an extent pool to an available disk list. It may be determined, for a Mapped RAID group, that each RAID extent in a sub group has not been allocated. At least one RAID extent in the sub group may be allocated based upon, at least in part, determining that each RAID extent in a sub group has not been allocated.

Abstract: A method and device for selecting a Redundant Array of Independent Disks (RAID) level for mapped RAID. The method comprises determining, for a given RAID level, a desired ratio of rebuilding speed between the mapped RAID and non-mapped RAID based on the first number of disks in the non-mapped RAID and the second number of disks in the mapped RAID. The method also comprises determining an actual ratio of rebuilding speed between the mapped RAID and the non-mapped RAID based on the second number of disks in the mapped RAID. In addition, the method comprises selecting the given RAID level for the mapped RAID in response to the actual ratio being above the desired ratio.

Abstract: Embodiments of the present disclosure provide a solution of evaluating a rebuilding performance of a redundant array of independent disks. In some embodiments, there is provided a computer-implemented method, comprising: simulating, based on a first group of redundant arrays of independent disks, a rebuilding process for a second group of redundant arrays of independent disks; obtaining a first performance metric of the simulated rebuilding process; and identifying a factor associated with the rebuilding performance of the second group of redundant arrays of independent disks based on the first performance metric.

Abstract: Embodiments of the present disclosure relate to method and apparatus for scaling out storage devices, and scaled-out storage devices by establishing a cross-device link between a first storage device and a second storage device; exchanging configuration information of at least one of the first storage device and the second storage via the cross-device link; creating, in the first storage device, a shadow object corresponding to a real object in the second storage device; and creating, in the second storage device, a shadow object corresponding to a real object in the first storage device; wherein each shadow object can expose feature and/or state of a corresponding real object to users without implementing a functioning logic of the corresponding real object.