Abstract: A technique manages a computing system based on a client/server architecture. In particular, an address mapping of a storage system is managed. The address mapping includes an association between storage spaces in a plurality of storage devices in the storage system and a user of the storage system. A data access service is provided to a client associated with the user based on the address mapping. The client includes at least any one of a user data client for accessing user data associated with the user in the storage system and a control data client for accessing control data associated with the user. Based on a client/server architecture, a uniform management mode is provided for user data and control data, so that the storage system is managed more simply and effectively.

Abstract: A technique maintains availability of a non-volatile cache. The technique involves arranging a plurality of non-volatile random-access memory (NVRAM) drives into initial drive sets that form the non-volatile cache. The technique further involves detecting a failed initial drive set among the initial drive sets. The plurality of NVRAM drives now includes failed NVRAM drives that belong to the failed initial drive set and remaining non-failed NVRAM drives. The technique further involves, in response to detecting the failed initial drive set, re arranging the remaining non-failed NVRAM drives of the plurality of NVRAM drives into new drive sets that form the non-volatile cache.

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 for storage management involve: determining expected usage time of a first storage disk in a set of storage disks, at least a part of the set of storage disks being configured to form at least one redundant array of independent disks (RAID); moving data in a first storage block, associated with a first RAID in the at least one RAID, in the first storage disk to a second storage block in a second storage disk in the set of storage disks based on a determination that the expected usage time is less than a predetermined threshold value; and replacing the first storage block with the second storage block, so that the second storage block is associated with the first RAID. Based on this manner, the stability of a storage system can be improved.

Abstract: A storage management technique involves: selecting a first disk from a plurality of disks in a storage system as an anchor disk; allocating a first backup slice from the plurality of disks to a redundant array of independent disks (RAID) associated with the first disk, the first RAID including at least a slice allocated from the first disk; and if it is detected that there is an inaccessible disk in the plurality of disks, determining a backup slice for a slice of the inaccessible disk based on the allocation of the first backup slice to the first RAID, for use in data reconstruction of the inaccessible disk. This can ensure that a backup slice can always be successfully determined for slices of an inaccessible disk without introducing additional time complexity.

Abstract: Techniques for managing storage blocks involve: according to a first request for allocating a target number of consecutive storage blocks from a storage device, querying an index table that is used to record index information of a plurality of groups of consecutive idle storage blocks in the storage device to determine a first group of consecutive idle storage blocks from the plurality of groups of consecutive idle storage blocks; allocating the target number of consecutive storage blocks from the first group of consecutive idle storage blocks; updating a bitmap that is used to record states of a plurality of storage blocks in the storage device; and updating first index information of the first group of consecutive idle storage blocks recorded in the index table. Accordingly, such techniques may reduce storage complexity and improve system performance.

Abstract: Techniques providing I/O control involve: in response to receiving an I/O request, detecting a first set bits for a stripe in a RAID. The RAID is built on disk slices divided from disks. The stripes include extents. Each of the first set bits indicates whether a disk slice where a corresponding extent in the stripe is located is in a failure state. The techniques further involve determining, from the stripe and based on the first set bits, a first set of extents in the failure state and a second set of extents out of the failure state. The techniques further involve executing the I/O request on the second set of extents without executing the I/O request on the first set of extents. Such techniques can simplify storage bits in I/O control, support the degraded stripe write request for the RAID and enhance performance executing the I/O control.

Abstract: Techniques involve: determining, according to a determination that a performance level of a target storage unit is lower than a threshold level, whether idle disk slices that can be used for reconstructing malfunctioning disk slices in the target storage unit exist in a slice pool; determining a priority of the target storage unit according to a determination that the idle disk slices do not exist; and selecting replacing disk slices for reconstructing the malfunctioning disk slices from available storage units based at least in part on the priority, wherein the available storage units have performance levels not lower than the threshold level. In this way, data loss due to the off-line of storage units is prevented; and meanwhile, the performance of the entire storage system can be globally stabilized.

Abstract: Techniques for managing a redundant array of independent disks (RAID) involve detecting an abnormality of a storage device in a RAID. The techniques further involve resetting the storage device in response to detecting the abnormality. The techniques further involve storing an address of a write operation for the RAID within a preset time period, so as to rebuild the RAID in the case that the storage device is recovered within the preset time period. Accordingly, temporary errors of the RAID can be efficiently handled, the number of downtime of the RAID caused by the storage device or the back end can be reduced, and computing resources and time required to rebuild the RAID can be significantly reduced.

Abstract: A technique maintains availability of a non-volatile cache. The technique involves arranging a plurality of non-volatile random-access memory (NVRAM) drives into initial drive sets that form the non-volatile cache. The technique further involves detecting a failed initial drive set among the initial drive sets. The plurality of NVRAM drives now includes failed NVRAM drives that belong to the failed initial drive set and remaining non-failed NVRAM drives. The technique further involves, in response to detecting the failed initial drive set, re arranging the remaining non-failed NVRAM drives of the plurality of NVRAM drives into new drive sets that form the non-volatile cache.

Abstract: Techniques for storage management involve: in response to a first disk becoming offline and remaining offline until a first time point, selecting a second storage slice in a second disk as a backup storage slice for a first storage slice in the first disk, the first storage slice being one of slices forming a redundant array of independent disks (RAID), the slices being located in different disks. The techniques further involve: writing, between the first time point and a second time point, data to be written into the first storage slice in the RAID to the second storage slice, the second time point being later than the first time point. The techniques further involve: in response to the first disk remaining offline until the second time point, replacing the first storage slice in the RAID with the second storage slice. Such techniques may improve performance of a RAID-based storage system.

Abstract: Techniques are used for improving performance of a storage system. The techniques may be used to provide, among other things, a set of counters for an object. Each counter corresponds to a unique processor in a multi-processor storage system. The state of a gate governing the object is determined. If the state of the gate is open, the counter corresponding to the first processor is incremented. The state of the gate for the object is re-determined. If the state of the gate remains open, the object is read and the counter corresponding to the first storage processor is decremented.

Abstract: A technique involves: in response to a stripe being created in a Redundant Array of Independent Disks (RAID), allocating to the stripe a storage space for storing a predetermined number of mapping information elements; creating one or more mapping information elements for the stripe; storing the one or more mapping information elements in the storage space; allocating respective storage sequence numbers to the one or more mapping information elements stored in the storage space; and in response to receiving an I/O request for the stripe indicating one of the respective storage sequence numbers, accessing the stripe based on the mapping information element in the storage space that is corresponding to the storage sequence number indicated by the I/O request. Such a technique can facilitate when disks encounter “glitch issues” simultaneously under extreme situations and effectively improve I/O read and write performance of a storage system.

Abstract: Techniques involve: determining a source disk slice from a plurality of disk slices of a plurality of storage arrays providing redundant storage, target data on the source disk slice needing to be removed; determining a destination disk slice for storing the target data needing to be removed from the source disk slice, a destination disk where the destination disk slice is located being different from a source disk where the source disk slice is located; and moving the target data from the source disk slice to the destination disk slice. Accordingly, such techniques can improve efficiency of a storage system.

Abstract: Techniques involve detecting whether a transaction of modifying configuration data of a storage system is initiated, the configuration data being stored in a database and a buffered version being stored in memory independent of the database. The techniques further involve in accordance with detection that the transaction is initiated, building a data buffer to buffer a section to be modified, the data buffer being mapped to a storage sector of the memory in which the section is expected to be stored. The techniques further involve determining whether the transaction successfully completed and in accordance with a determination that the transaction fails to successfully complete, releasing the data buffer and aborting the transaction, without modifying the buffered version. Accordingly, the configuration data in the memory remains as the previous version and are not modified before the transaction is successfully completed, which makes it possible to abort the transaction.

Abstract: Techniques for managing a storage unit involve: determining space usage indicators of a storage system including disks, each disk is divided into disk slices, and at least part of the disk slices are organized into a storage unit. The techniques further involve: determining a target priority of a data migration task based on the space usage indicators, wherein the data migration task is used to migrate data in a group of disk slices allocated to at least one storage unit to another group of disk slices. The techniques further involve: if the target priority is different from a current priority of the data migration task, adjusting the current priority of the data migration task to the target priority, and determining system resources for the data migration task based on the target priority. Accordingly, a priority of a data migration task can be dynamically adjusted to accommodate different scenarios.

Abstract: Techniques for managing a storage system involve flushing a target page in a cache device to a persistent storage device of the storage system. The techniques further involve releasing a resource storing a page descriptor of the target page to a resource pool. The resource pool is configured to provide resources to store page descriptors of pages to be flushed in the cache device. The techniques further involve: if it is determined that an auxiliary descriptor of the target page is located at a tail of a queue of auxiliary descriptors of the pages to be flushed, removing the auxiliary descriptor of the target page from the queue. The auxiliary descriptors of the pages to be flushed are configured to describe the page descriptors of the pages to be flushed. Accordingly, the page flushing performance of the storage system can be improved, thereby improving the input/output performance.

Abstract: Techniques for managing storage blocks involve: according to a first request for allocating a target number of consecutive storage blocks from a storage device, querying an index table that is used to record index information of a plurality of groups of consecutive idle storage blocks in the storage device to determine a first group of consecutive idle storage blocks from the plurality of groups of consecutive idle storage blocks; allocating the target number of consecutive storage blocks from the first group of consecutive idle storage blocks; updating a bitmap that is used to record states of a plurality of storage blocks in the storage device; and updating first index information of the first group of consecutive idle storage blocks recorded in the index table. Accordingly, such techniques may reduce storage complexity and improve system performance.

Abstract: Storage management techniques involve: acquiring target data in a target storage page in a memory; determining, based on the target data, check information and identification information associated with the target data, the check information being used to verify whether the target data is correct and the identification information being used to identify the target data; and determining, based on the identification information, storage information associated with the target data and the check information, the storage information indicating whether to store the target data and the check information to a persistent storage device. Therefore, the processing efficiency can be improved, and the input/output (I/O) performance can be improved.

Abstract: A storage management technique involves: selecting a first disk from a plurality of disks in a storage system as an anchor disk; allocating a first backup slice from the plurality of disks to a redundant array of independent disks (RAID) associated with the first disk, the first RAID including at least a slice allocated from the first disk; and if it is detected that there is an inaccessible disk in the plurality of disks, determining a backup slice for a slice of the inaccessible disk based on the allocation of the first backup slice to the first RAID, for use in data reconstruction of the inaccessible disk. This can ensure that a backup slice can always be successfully determined for slices of an inaccessible disk without introducing additional time complexity.