Abstract: Various techniques manage a storage system. Such techniques involve: in response to detecting that a first request of a plurality of requests initiated for a bulk request is completed, determining a response time length for the first request, the bulk request being used to migrate data from a first storage device to a second storage device, each request of the plurality of requests being used to read data from the first storage device and write data to the second storage device; determining an average response time length of the completed requests of the plurality of requests based at least in part on the response time length for the first request; and updating the number of the plurality of requests initiated for the bulk request based on the average response time length.

Abstract: Techniques involve writing to a disk array. In response to a request for writing target data to a target storage area in a stripe of the disk array including at least one failed storage area, it is determined whether incompletion of the writing of the target data is to cause failed data in the at least one failed storage area to be unrecoverable. In response to determining that the incompletion of the writing is to cause failed data to be unrecoverable, the failed data is recovered. The recovered data is stored in a persistent memory, and the target data is written in the target storage area. In this way, the efficiency and performance of writing processing of the disk array having a failed disk is increased significantly.

Abstract: Techniques perform failure recovery of a storage device. The techniques involve: determining, based on failure data indicating at least one failed disk, whether the at least one failed disk comprises a system disk associated with an extent pool of the storage device, the extent pool being built based on system disks and user disks; in response to determining that the at least one failed disk comprises a system disk, rebuilding the user data of the system disk to one or more further disks associated with the extent pool; and in response to the system disk being replaced with an updated system disk, restoring the rebuilt user data from the one or more further disks to the updated system disk, an association of the system disk with the extent pool being maintained until the system disk is replaced by the updated system disk.

Abstract: Techniques manage a storage system comprising a group of storage devices. The techniques involve: determining from the group of storage devices a first storage device which is in a rebuilding state; in response to a second storage device in the group of storage devices failing, obtaining a recoverability indication indicating whether a data block in the second storage device, which corresponds to a target data block in the first storage device, is recoverable or not on the basis of a data state of the target data block; and recovering data in the data block in the second storage device corresponding to the target data block on the basis of the recoverability indication.

Abstract: A storage management technique involves: receiving a request for creating a virtual volume, the request at least indicating a size and a service level of the virtual volume; in response to the request, creating the virtual volume on a first storage device; storing metadata information of the virtual volume in a local database that is accessible to the first storage device, the metadata information at least comprising identification information of the virtual volume and identification information of the first storage device; and synchronizing the metadata information to at least one second storage device. Such a technique enables more flexible creation of virtual volumes on a cluster of storage device.

Abstract: Techniques perform storage management. Such techniques involve, in response to an operation to be performed on data in a cache page, determining a first cache page reference corresponding to the cache page, the first cache page reference comprising a pointer value indicating the cache page. Such techniques further involve creating, based on the first cache page reference and the operation, a second cache page reference corresponding to the cache page, the second cache page reference comprising the pointer value. Such techniques further involve performing the operation on the data in the cache page via the second cache page reference. One cache page can correspond to a plurality of cache page references. Additionally, copy of data from one cache page to a further cache page can be effectively avoided, so as to enhance input/output performance and utilization rate of storage space.

Abstract: Techniques for managing metadata at a control device involve: determining, from a cache page corresponding to user data, a first region for storing raw metadata of the user data, the raw metadata including address information for storing the user data in a storage system; in response to the user data being modified, determining updated metadata of the modified user data to update the raw metadata in the first region; and copying the updated metadata to a high-speed memory shared by the control device and another control device. Accordingly, the techniques are capable of reducing the usage frequency of the high-speed memory, thereby extending the service life of the high-speed memory and reducing cost.

Abstract: Techniques recognize reducible contents in data to be written. The techniques involve receiving information related to data to be written, the information indicating that the data to be written comprises reducible contents, the reducible contents comprising data with a first reduction pattern. The techniques further involve recognizing the reducible contents in the data to be written based on the information. The techniques further involve reducing the reducible contents based on the first reduction pattern. With such techniques, active I/O pattern recognition with communication between applications and storage devices may be accomplished. In addition, with such techniques, it is easy/simple to expand recognizable new patterns, and I/O pattern limitations in standard approaches no longer exist.

Abstract: Embodiments of the present disclosure relate to communications between virtual dual control modules in a virtual machine environment. A computer-implemented method and an electronic device are disclosed. The method includes deploying a first virtual control module and a second virtual control module in a virtual storage, the first virtual control module and the second virtual control module are redundant with each other. The method further comprises creating a virtual Peripheral Component Interconnect Express (PCIe) switch for emulating a physical PCIe switch, and synchronizing cache data between the first virtual control module and the second virtual control module via the virtual PCIe switch.

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: In accordance with certain techniques, at a first processor of a dual-processor storage system, a change in an initial logical unit corresponding to a storage area in a physical storage device of the storage system is detected. Based on the change in the initial logical unit, a plurality of update operations to be performed on a mapped logical unit driver mapping a plurality of initial logical units including the initial logical unit to a plurality of mapped logical units are determined. An indication of the plurality of update operations is sent to a second processor of the storage system, to cause the second processor to perform the plurality of update operations on a peer mapped logical unit driver associated with the mapped logical unit driver.

Abstract: Techniques perform data recovery. The techniques involve: in response to receiving to-be-written data at a first cache module, storing metadata in the data into a first non-volatile cache of the first cache module. The techniques further involve storing user data in the data into a first volatile cache of the first cache module. The techniques further involve sending the metadata and the user data to a second cache module for performing data recovery on the user data. Accordingly, a larger and better guaranteed data storage space may be provided to a cache data backup/recovery system without a need to increase the battery supply capacity and even without a battery.

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.

Abstract: A computer-implemented method for establishing a multi-tier flash cache using spare drives. The method includes, in response to receiving an I/O request, determining that there is no free page in a main cache. Having determined that there is no free page in the main cache, the method further includes establishing a secondary cache by selecting at least one spare drive from a plurality of spare drives, flushing data from a cold page in the main cache to the secondary cache, an access frequency of the cold page being lower than a predetermined threshold, and writing data related to the I/O request from a persistent storage device to the cold page.

Abstract: Embodiments of the present disclosure relate to a method and device for flushing pages from a solid-state storage device. Specifically, the present disclosure discloses a method of flushing pages from a solid-state storage device comprising: determining a first number based on a period length of one flushing cycle and a period length required for building one flushing transaction, the first number indicating a maximum number of flushing transactions that can be built in the flushing cycle; and flushing pages from the solid-state storage device with an upper limit of the first number in the flushing cycle. The present disclosure also discloses a device for flushing pages from a solid-state storage device and a computer program product for implementing steps of a method of flushing pages from a solid-state storage device.

Abstract: A method and an apparatus for data storage system are provided. The method comprises: receiving an I/O request from an upper layer, the I/O request including an I/O type identifier; determining an I/O type of the I/O request based on the I/O type identifier; and processing the I/O request based on the determined I/O type. The present disclosure also provides a corresponding apparatus. The method and the apparatus according to the present disclosure can determine a storage policy of corresponding data based on different I/O types to improve the overall system performance.

Abstract: A method and a system for delivering a message in a storage system. In one embodiment of the present invention, there is provided a method for delivering a message in a storage system comprising a first controller, a second controller, a first communication area and a second communication area. The method comprises: in response to receiving a message that is to be delivered from the first controller to the second controller, writing the message to the first communication area that is readable and writable to the first controller and readable to the second controller; and writing an address identifier to the second communication area, the address identifier being used for indicating an address at which the second controller reads the message from the first communication area, the second communication area being readable to the first controller and readable and writable to the second controller.

Abstract: A method, computer program product, and computer system for receiving, by a computing device, one or more drives added to an extent pool of storage devices. An empty Mapped RAID group may be generated. A plurality of extents in the extent pool may be shuffled. A RAID extent may be mapped to the empty Mapped RAID group, wherein the RAID extent is mapped to the empty Mapped RAID group while shuffling the plurality of extents in the extent pool.

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 invention relate to a method and system for managing data access in a storage system. A method for managing data access in a storage system, the method comprising: obtaining state information about available resources in a storage control node in the storage system; determining, based on the state information, a credit score descriptive of processing capacity of the storage control node for data access; and publishing the credit score so as to notify a host of the processing capacity of the storage control node for the data access.