Abstract: Embodiments of the present disclosure relate to method, device and computer program product for data backup. The method comprises: in response to receiving from a backup server a data stream to be backed up, dividing the data stream into a plurality of data segments; distributing the plurality of data segments to at least one computing node; in response to receiving an index of a corresponding data segment from a first computing node of the at least one computing node, looking up the index in a global index cache, the index being generated by the first computing node to uniquely identify the data segment, the global index cache storing indexes of data in a backup storage device; in response to the missing index in the global index cache, adding the index into the global index cache; and sending to the first computing node an indication to store the data segment in the backup storage device.

Abstract: Techniques for managing data blocks involve: generating, based on a first hash algorithm, a first fingerprint for a first block. The techniques further involve: if it is determined that there is a second fingerprint, in a fingerprint database, that is generated for a second block based on the first hash algorithm and matches the first fingerprint, determining whether there is a third fingerprint, in the fingerprint database, that is generated for the second block based on a second hash algorithm. The techniques further involve: if it is determined that the third fingerprint exists in the fingerprint database, generating a fourth fingerprint for the first block based on the second hash algorithm; and determining whether the first block and the second block are duplicate by comparing the third fingerprint and the fourth fingerprint. Such techniques can effectively reduce the overhead of identifying duplicate data blocks in data deduplication.

Abstract: Techniques provide for managing storage devices. Such techniques involve: combining storage devices in a redundant array of independent disks into a group of storage devices in an order of physical capacities of the storage devices; determining a first number of sets of storage devices based on a number of storage devices in the group and a threshold number of storage devices to be divided into each of the sets; and dividing, based on a configuration of the redundant array of independent disks, the group of storage devices into the first number of sets of storage devices, to optimize an effective capacity of the redundant array of independent disks.

Abstract: Techniques for managing a storage system involve: based on a degree of importance of data stored in a persistent storage device of the storage system, determining key data from the data, wherein a degree of importance of the key data is higher than a threshold degree; respectively identifying first data corresponding to the key data in a first cache of the storage system and second data corresponding to the key data in a second cache of the storage system as non-removable; and in response to corruption of the first data, repairing the first data using the second data in the second cache. Such techniques can avoid system shutdown caused by corruption of key data.

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 for managing a storage system involve: based on a degree of importance of data stored in a persistent storage device of the storage system, determining key data from the data, wherein a degree of importance of the key data is higher than a threshold degree; respectively identifying first data corresponding to the key data in a first cache of the storage system and second data corresponding to the key data in a second cache of the storage system as non-removable; and in response to corruption of the first data, repairing the first data using the second data in the second cache. Such techniques can avoid system shutdown caused by corruption of key data, thereby optimizing system performance.

Abstract: Techniques perform storage management. Such techniques involve: in response to receiving, at a first processor of a storage system, a write request from a host for writing user data, caching the user data in a first cache of the first processor, and generating cache metadata in the first cache, the cache metadata including information associated with writing the user data; sending the user data and the cache metadata to a second cache of a second processor, for the second processor to perform, in the second cache, data processing related to cache mirroring by the second processor; and sending, to the host, an indication of completion of the write request, without waiting for the second processor to complete the data processing. Such techniques can improve system performance such as reducing latency, and shortening length of the I/O handling path of write request.

Abstract: Techniques for managing data blocks involve: generating, based on a first hash algorithm, a first fingerprint for a first block. The techniques further involve: if it is determined that there is a second fingerprint, in a fingerprint database, that is generated for a second block based on the first hash algorithm and matches the first fingerprint, determining whether there is a third fingerprint, in the fingerprint database, that is generated for the second block based on a second hash algorithm. The techniques further involve: if it is determined that the third fingerprint exists in the fingerprint database, generating a fourth fingerprint for the first block based on the second hash algorithm; and determining whether the first block and the second block are duplicate by comparing the third fingerprint and the fourth fingerprint. Such techniques can effectively reduce the overhead of identifying duplicate data blocks in data deduplication.

Abstract: A method, computer program product, and computing system for receiving one or more IO requests at a cache system for storing content in a storage array. A maximum number of concurrent backend IO requests may be associated with the storage array based upon, at least in part, a change in size of the storage array. The one or more TO requests may be flushed to the storage array via one or more backend IO requests from the cache system based upon, at least in part, the maximum number of concurrent backend IO requests associated with the storage array.

Abstract: Embodiments of the present disclosure relate to a method and apparatus for managing cache. The method comprises determining a cache flush time period of the cache for a lower-layer storage device associated with the cache. The method further comprises: in response to a length of the cache flush time period being longer than a threshold length of time, in response to receiving a write request, determining whether data associated with the write request has been stored into the cache. The method further comprises: in response to a miss of the data in the cache, storing the write request and the data in the cache without returning a write completion message for the write request.

Abstract: Embodiments of the present disclosure relate to methods, devices and computer readable mediums for data synchronization. A method comprises in response to receiving, at a first processor, a first request to synchronize data, initiating, to a second processor, a first remote direct memory access (RDMA) operation for transmitting the data between a first cache in the first processor and a second cache in the second processor. The method further comprises in response to completion of the first RDMA operation, writing the data into a first persistent storage device coupled to the first processor. The method further comprises transmitting, to the second processor, a command to instruct the second processor to commit the data to a second persistent storage device coupled to the second processor. Moreover, the method further comprises detecting, from the second processor, an acknowledgement for the command, the acknowledgement indicating that the data is synchronized between the first and second processors.

Abstract: Embodiments of the present invention provide a method and system for managing a storage area. In one embodiment of the present invention, there is provided a method for managing a storage areas, comprising: obtaining a storage area in a storage system according to a predefined dividing rule; determining status regarding whether the storage area has been used; setting a status identifier for the storage area based on the use status; and managing the storage area based on the status identifier. In another embodiment, there is proposed a system for managing a storage area, comprising: one or more processors; a memory coupled to at least one processor of the one or more processors; computer program instructions stored in the memory which, when executed by the at least one processor, cause the system to execute a method for managing a storage area.

Abstract: Techniques perform data storage. Such techniques may involve writing metadata to a first cache of a first processor, the metadata indicating allocation of a storage resource to user data. Such techniques may further involve determining an address range of the metadata in the first cache. Such techniques may further involve copying only data stored in the address range in the first cache to a second cache of a second processor. Accordingly, the data transmission volume between two processors is reduced, which helps to improve the overall performance of a storage system.

Abstract: Techniques involve: in response to adding a second set of disks into a redundant array of independent disks (RAID) including a first set of disks and a total number of disks in the first and second sets exceeding a predetermined threshold, determining types and numbers of disks in the first and second sets, respectively; determining, based on the types and numbers of the disks determined and a performance indicator of the RAID having the added second set, respective types and numbers of disks comprised in a plurality of sets to which the disks in the RAID are to be allocated; and performing, based on the type and number of disks in the first set and the respective types and numbers of disks, an allocation of a disk in the first set to one of the plurality of sets, until all the disks in the first set have been allocated.

Abstract: Techniques manage an input/output (I/O) operation. Such techniques involve estimating a first storage area in a storage device to be accessed by an upcoming random I/O operation, first data being stored in the estimated first storage area. Such techniques further involve, before the random I/O operation is executed, pre-fetching the first data from the first storage area into a cache associated with the storage device. Such techniques enable implementation of the cache pre-fetch for random I/O operations, thereby effectively improving the performance of data access.

Abstract: A method is used in validating data in a storage system. The method writes host data to the storage system during processing of a host I/O operation, where the host is in communication with the storage system. The storage system writes host data and test data associated with the host data to a storage device of the storage system. The method reads the host data and the test data from the storage device for validating the host data, and evaluates the test data to determine whether the host data has been written correctly by the storage system to the storage device. Upon determining that the host data has not been written correctly by the storage system to the storage device due to a failure, the method evaluates the test data to determine a cause of the failure.

Abstract: Techniques perform data writing. Such techniques involve: in response to receiving a first write request, searching a cache for a target address associated with the first write request; in response to missing of the target address in the cache, determining a page usage rate in the cache; and in response to determining that the page usage rate exceeds an upper threshold, performing the first write request with a first available page in the cache. The first available page is reclaimed, independent of a refresh cycle of the cache, in response to completing the performing of the first write request.

Abstract: Techniques for allocating storage disks involve: determining, from storage disks to be allocated, groups of storage disks, where each of groups of storage disks includes storage disks corresponding to one disk array; selecting, from the groups of storage disks, a group of target storage disks, the group of target storage disks having an unavailable capacity lower than a first capacity threshold; and creating, based on the storage disks, a storage disk set including at least the group of target storage disks. Accordingly, the storage disk set with optimized available capacity may be found with fewer computing overheads.

Abstract: Embodiments of the present disclosure provide a method, an apparatus and a computer program product for managing an input/output (I/O). The method comprises, in response to receiving a first I/O request of a first type for a storage device, determining whether there exists at least one credit available to the first type of I/O requests. Each of the at least one credit indicates I/O processing capability reserved by the storage device for the first type of I/O requests. The method further comprises allocating a first credit to the first I/O request based on a result of the determining. The method further comprises performing, by using the first credit, an I/O operation requested by the first I/O request on the storage device. Moreover, the method further comprises, in response to completion of the I/O operation, recycling the first credit for use by a subsequent I/O request. Embodiments of the present disclosure can implement dynamic allocation of I/O processing capability for different types of I/Os.

Abstract: Techniques manage a storage system. The techniques involve: in response to a first control unit of the storage system receiving an access request to a target storage area in the storage system, determining whether the target storage area is located in a first storage area or a second storage area; in response to the target storage area being located in the second set of storage areas, determining that a second control unit of the storage system processes the access request, the first control unit and the second control unit sharing the storage system; and updating an access state of the first control unit to the target storage area, the access state indicating access permission for the target storage area included in the first control unit. Such techniques can effectively reduce the number of CMI messages related to a stripe lock mechanism in a dual active SP.