Abstract: Techniques lock a storage area in a storage system including a first storage node and a second storage node. Such techniques involve adjusting a value of at least one of a first counter at the first node and a second counter at the second node in response to receiving a data access request for the storage area at at least one of the first node and the second node. Such techniques further involve allocating a lock flag to the first node in response to a ratio of the value of the first counter to the value of the second counter being greater than a first threshold, the lock flag indicating that the storage area is locked by the first node. Accordingly, storage resources required by nodes that are accessed more frequently in statistics are effectively reduced, and the efficiency of applying stripe lock reduction are improved.

Abstract: Techniques manage tracking records in an application system which includes an active dump file and an inactive dump file. A set of tracking records indicating a state of the application system is received. The set of tracking records is added to the active dump file. A storage signal for storing the active dump file into a backup device associated with the application system is generated according to a determination that a size of the active dump file meets a predetermined size threshold and according to a determination that a state of the inactive dump file is a ready state. The ready state indicates that the inactive dump file is available for storing another set of tracking records to be received in the future. Accordingly, two dump files may alternately store tracking records, and copies of the dump files may be continuously stored into a backup device to improve reliability.

Abstract: Techniques for accessing data involve reading data from at least one disk among a plurality of disks. Such techniques further involve detecting whether a lookup table stored on a memory is empty, where the lookup table stores information indicating data loss. Such techniques further involve comparing, in response to the lookup table not being empty, data read information associated with the read data with table items in the lookup table to determine whether there is a table item in the lookup table that matches the data read information. Such techniques further involve sending, in response to determining that there is a table item that matches the data read information, the information indicating data loss. Such a technique improve the efficiency of data access, reduces the complexity of the system and the power consumption of the system, and improves the performance of the system.

Abstract: Techniques for double parity RAID are disclosed. For example, a system includes a processor coupled to a memory. The processor is configured to: receive a request to store data in data storage disks, wherein the received data is segmented into data blocks; create a distributed parity block P, wherein the distributed parity block is calculated based on the data; select a given data storage disk among the data storage disks to store the distributed plurality block, wherein the given data storage disk is rotated among the data storage disks; write the data blocks to each data storage disk among the data storage disks except the selected data storage disk; write the distributed parity block to the selected data storage disk; create a dedicated parity block Q, wherein the dedicated parity block is calculated based on the data; and write the dedicated parity block to a parity disk.

Abstract: Techniques for processing write conflicts involve determining, in response to receiving a write operation for a stripe, a state of a backend operation of a stripe set, wherein the backend operation includes one of a rebuilding or re-striping operation. The techniques further involve stopping the write operation in response to the state of the backend operation indicating that the backend operation is being executed in the stripe. The techniques further involve executing the write operation in response to the state of the backend operation indicating that the backend operation is not being executed in the stripe. Accordingly, write conflicts between a write operation and a backend operation for the same stripe can be favorably avoided, and concurrent execution of the write operation and the backend operation simultaneously for the same stripe is prevented, thus preventing the deterioration of a storage system and improving storage system security and stability.

Abstract: An error injection technique involves: receiving a logic error including an injection address parameter and an injection error parameter, and matching the injection address parameter in the logic error with a request address parameter in a response to a data request in at least one workflow. The technique further involves: in a case that the injection address parameter is matched with the request address parameter, injecting the injection error parameter into the response to the data request. Such a technique provides a flexible error injection mode, which may fully test the reliability and availability of storage devices, thereby providing high-quality storage services for users.

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: Techniques for storage management involve determining a plurality of storage units to be reconstructed on a group of disks, the plurality of storage units being distributed on different disks in the group of disks. Such techniques further involve selecting, based on the distribution of the plurality of storage units on the group of disks, a group of storage units from the plurality of storage units so that different storage units in the group of storage units are distributed on different disks. Such techniques further involve performing concurrent reconstruction on the group of storage units.

Abstract: Techniques for storage management involve determining, in response to a detection that a disk changes from an unavailable state to an available state, at least one candidate storage unit associated with the disk; acquiring historical access information about the at least one candidate storage unit, the historical information comprising information related to a write request directed to the at least one candidate storage unit when the disk is in the unavailable state; determining a target storage unit from the at least one candidate storage unit based on the historical access information; and rebuilding the target storage unit. Such techniques may, in a low-cost manner, improve rebuilding efficiency and reliability of a storage system.

Abstract: Techniques lock a storage area in a storage system including a first storage node and a second storage node. Such techniques involve adjusting a value of at least one of a first counter at the first node and a second counter at the second node in response to receiving a data access request for the storage area at at least one of the first node and the second node. Such techniques further involve allocating a lock flag to the first node in response to a ratio of the value of the first counter to the value of the second counter being greater than a first threshold, the lock flag indicating that the storage area is locked by the first node. Accordingly, storage resources required by nodes that are accessed more frequently in statistics are effectively reduced, and the efficiency of applying stripe lock reduction are improved.

Abstract: Techniques for accessing data involve reading data from at least one disk among a plurality of disks. Such techniques further involve detecting whether a lookup table stored on a memory is empty, where the lookup table stores information indicating data loss. Such techniques further involve comparing, in response to the lookup table not being empty, data read information associated with the read data with table items in the lookup table to determine whether there is a table item in the lookup table that matches the data read information. Such techniques further involve sending, in response to determining that there is a table item that matches the data read information, the information indicating data loss. Such a technique improve the efficiency of data access, reduces the complexity of the system and the power consumption of the system, and improves the performance of the system.

Abstract: Techniques perform storage management. The techniques involve: in response to a target request for a target redundant array of independent disks (RAID), determining that data in a first storage block associated with the target RAID needs to be moved or copied, wherein the target request includes one of the following: a restriping request, a type conversion request, or a rebalancing request; creating an intermediate RAID associated with an idle second storage block; and copying the data in the first storage block to a corresponding storage space in the intermediate RAID to write at least part of the data in the second storage block. Based on this mode, RAID restriping, type conversion, or rebalancing can be implemented efficiently.

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: Techniques for storage management involve determining a plurality of storage units to be reconstructed on a group of disks, the plurality of storage units being distributed on different disks in the group of disks. Such techniques further involve selecting, based on the distribution of the plurality of storage units on the group of disks, a group of storage units from the plurality of storage units so that different storage units in the group of storage units are distributed on different disks. Such techniques further involve performing concurrent reconstruction on the group of storage units.

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 data recovery involve: reading target data corresponding to a first logical block from a first data block of a stripe of a RAID system, the target data being a compressed version of data in the first logical block; in accordance with a determination that an error occurs in the target data, reading data from a plurality of second data blocks of the stripe and first parity information from a first parity block of the stripe; comparing respective checksums of the data read from the plurality of second data blocks with a first predetermined checksum and a checksum of the first parity information with a second predetermined checksum; and determining recoverability of the target data based on a result of the comparison. Accordingly, it is possible to simplify the data recovery process, reduce the calculation and time costs in the data recovery, and improve the data recovery efficiency.

Abstract: In creating an extent array in a storage system, in response to receiving a request to generate an extent array using idle extents in storage devices, a width of an extent stripe is determined, and a size of the extent array is designated by the storage system. A first extent group and a second extent group are respectively selected from the storage devices based on the width to form a first extent stripe and a second extent stripe, and a first extent at a given position in the first extent group and a second extent at a given position in the second extent group are respectively located in different storage devices. Based on the first extent stripe and the second extent stripe, an address mapping representing the extent array is generated. The address mapping includes association between extent identifiers of extents and extent indexes of the extents.

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: In response to receiving a read request for target data, an external address of the target data is obtained from the read request, which is an address unmapped to a storage system; hit information of the target data in cache of the storage system is determined based on the external address; and based on the hit information, an address from the external address and an internal address for providing the target data is determined. The internal address is determined based on the external address and a mapping relationship. Therefore, it can shorten the data access path, accelerate the responding speed for the data access request, and allow the cache to prefetch the data more efficiently.

Abstract: Techniques manage a redundant array of independent disks. In such a technique, a response time of a first storage device in the RAID is compared to a first threshold. In response to the response time of the first storage device exceeding the first threshold, the first storage device is configured as a pseudo-degraded storage device, such that the pseudo-degraded storage device is responsive to write requests only.