Abstract: A method for data storage includes defining a host cluster within a group of host computers, which access a storage system that includes multiple logical volumes. The host cluster includes two or more of the host computers. A single mapping instruction, which specifies the host cluster and a set of one or more of the logical volumes, is accepted. Responsively to the single mapping instruction, each of the host computers in the host cluster is mapped to access the logical volumes in the set. In another disclosed method, a single control instruction, which specifies the host cluster and a configuration operation to be applied to the host computers in the host cluster, is accepted. Responsively to the single control instruction, the configuration operation is applied to each of the host computers in the host cluster.

Abstract: A method for data storage includes defining a host cluster within a group of host computers, which access a storage system that includes multiple logical volumes. The host cluster includes two or more of the host computers. A single mapping instruction, which specifies the host cluster and a set of one or more of the logical volumes, is accepted. Responsively to the single mapping instruction, each of the host computers in the host cluster is mapped to access the logical volumes in the set. In another disclosed method, a single control instruction, which specifies the host cluster and a configuration operation to be applied to the host computers in the host cluster, is accepted. Responsively to the single control instruction, the configuration operation is applied to each of the host computers in the host cluster.

Abstract: A method is disclosed for operating a data storage system having one or more network interfaces and a plurality of data storage nodes configured to provide redundant storage locations. The method includes storing a set of node partitions on a given storage node of the plurality of data storage nodes. The method also includes, following a recovery by the given storage node from a malfunction, making a determination for a node partition in the set whether the node partition is current or noncurrent, and processing the node partition according to the determination.

Abstract: A method for operating a storage system, consisting of performing an allocation of respective partitions of a physical storage resource of the storage system to respective hosts of the storage system. The method also includes changing the allocation while permitting the respective hosts of the storage system to access the physical storage resource.

Abstract: Embodiments of the present invention provide methods, apparatuses, systems, and computer software products for data storage. A first copy of a logical volume is created. A second copy of the logical volume is created based on the first copy of the logical volume, such that the first and second copies are represented by respective first and second sets of pointers to physical storage locations in which data used by the copies is stored. Responsively to a corruption of at least part of the data that is used by the first copy. The first copy is restored from the second copy by replacing the first set with the pointers in the second set.

Abstract: A method for data storage includes creating first and second copies of a logical volume, such that the first and second copies are represented by respective first and second sets of pointers to physical storage locations in which data used by the copies is stored. Responsively to a corruption of at least part of the data that is used by the first copy, the first copy is restored from the second copy by replacing the first set with the pointers in the second set.

Abstract: A method for data distribution, including distributing logical addresses among an initial set of devices so as provide balanced access, and transferring the data to the devices in accordance with the logical addresses. If a device is added to the initial set, forming an extended set, the logical addresses are redistributed among the extended set so as to cause some logical addresses to be transferred from the devices in the initial set to the additional device. There is substantially no transfer of the logical addresses among the initial set. If a surplus device is removed from the initial set, forming a depleted set, the logical addresses of the surplus device are redistributed among the depleted set. There is substantially no transfer of the logical addresses among the depleted set. In both cases the balanced access is maintained.

Abstract: A method is disclosed for operating a data storage system having one or more network interfaces and a plurality of data storage nodes configured to provide redundant storage locations. The method includes storing a set of node partitions on a given storage node of the plurality of data storage nodes. The method also includes, following a recovery by the given storage node from a malfunction, making a determination for a node partition in the set whether the node partition is current or noncurrent, and processing the node partition according to the determination.

Abstract: A method for data distribution, including distributing logical addresses among an initial set of devices so as provide balanced access, and transferring the data to the devices in accordance with the logical addresses. If a device is added to the initial set, forming an extended set, the logical addresses are redistributed among the extended set so as to cause some logical addresses to be transferred from the devices in the initial set to the additional device. There is substantially no transfer of the logical addresses among the initial set. If a surplus device is removed from the initial set, forming a depleted set, the logical addresses oldie surplus device are redistributed among the depleted set. There is substantially no transfer of the logical addresses among the depleted set. In both cases the balanced access is maintained.

Abstract: A method is disclosed for operating a data storage system having one or more network interfaces and a plurality of data storage nodes configured to provide redundant storage locations. The method includes storing a set of node partitions on a given storage node of the plurality of data storage nodes. The method also includes, following a recovery by the given storage node from a malfunction, making a determination for a node partition in the set whether the node partition is current or noncurrent, and processing the node partition according to the determination.

Abstract: A system, method and circuit for efficiently managing a cache storage device. A cache storage device may include a cache management module. The cache management module may be adapted to generate a management unit and to associate the management unit with new data that is to be written into the cache. The cache management module may be further adapted to assign two or more allocation units for each management unit, to store the new data in the cache. A cache management module may include a management unit module. The management unit module may be adapted to generate management units associated with predefined global cache management functions. The cache management module may further include an allocation unit module in communication with the management unit module. The allocation unit module may be adapted to assign allocation units for storing data written into the cache.

Abstract: Upon receiving a request for one or a set of data blocks associated with a given data segment, a disk cache controller may retrieve into cache the some part of the entire data segment from a disk. Each data segment on a disk may include a fixed number of data blocks, and all data segments may include the same number of data blocks. Data segments may be dynamically defined and their locations and sizes may vary from segment to segment. Data segments may be defined when data is written to the disk, or may be defined at a later point. A table associated with a cache controller may store information as to the physical location or address on a disk of the starting point and/or size of each data segment.

Abstract: A method for data storage includes accepting a management command by a first storage controller, which exchanges data for storage with at least a second storage controller over a dedicated communication connection using a dedicated storage protocol. The management command is addressed to a destination storage controller and contains an instruction to modify or report a data storage configuration in the destination storage controller. Upon determining that the destination storage controller is different from the first storage controller, the management command is forwarded over the dedicated communication connection from the first storage controller to the second storage controller using the dedicated storage protocol.

Abstract: A storage system, consisting of one or more data storage logical units (LUs) formed in physical media. The LUs are adapted to receive command and respond to the commands to store and recall data. The storage system further includes a plurality of ports, each port being adapted to maintain a respective LU command queue for each of the LUs, such that upon receiving a command directed to one of the LUs, the port places the received command in the respective LU command queue. The port converts the received command to one or more converted commands at least some of which are directed to the physical media of the one of the LUs. The port then conveys the commands directed to the physical media in an order determined by the respective LU command queue.

Abstract: Exemplary methods, systems, and computer program product embodiments for concurrent upgrade of a plurality of components in a storage subsystem are provided. A plurality of upgraded components associated with an upgraded storage subsystem replaces a plurality of existing components associated with an existing storage subsystem. Support for a verify I/O command is created. A target volume is created in the upgraded storage subsystem having a same volume identification as a source volume. For a command received on the at least one of the plurality of upgraded components, the verify I/O command is invoked on at least one of a comparable one of the plurality of existing components. If the command is verified, the command is driven. The at least one of the plurality of upgraded components disguises a true volume identification of the target volume from the at least one of the plurality of existing components.

Abstract: A method for operating a data storage system that includes a plurality of mass storage devices, which are configured to store data redundantly, the method including determining a characteristic service level of one or more of the mass storage devices and defining a reduced service level, which is less than the characteristic service level. The method further includes performing the following steps automatically: detecting the reduced service level on a first mass storage device in the data storage system; determining that data on the first mass storage device is stored redundantly on a second mass storage device in the data storage system; and in response to detecting the reduced service level, diverting an input/output (IO) request for the data directed to the first mass storage device to the second mass storage device, while operating the first mass storage device at the reduced service level.

Abstract: A method for managing a data storage system, consisting of configuring a first cache to retrieve data from and store data at a first range of logical addresses (LAs) in a storage device. A second cache is configured to operate like the first cache. The method further includes configuring one or more third caches to retrieve data from and store data at a second range of LAs in the storage device. The method includes detecting an inability of the second cache to retrieve data from or store data at the first range of LAs. In response to the inability, at least one of the first cache and the one or more third caches are reconfigured to retrieve data from and store at the first range of LAs while continuing to retrieve data from and store at the second range of LAs.

Abstract: In accordance with some embodiments of the present invention, there is provided a cache management module for managing a cache memory device, comprising a groups management module adapted to define groups of allocation units in accordance with at least an operative criterion and to create a new group of allocation units whenever it is determined that in accordance with at least the operative criterion none of the one or more existing groups is appropriate to include an allocation unit, and a replacement procedure module adapted to manage the cache in terms of groups of allocation units, rather than in terms of discrete allocation units.

Abstract: Disclosed is a system and method from mirroring data from a data storage server/system. A mirroring module on a primary mirror server/system may forward one or more data packets received from the data storage server/system to a secondary mirror server/system. The one or more packets maybe received over a synchronous data link and forwarded over an asynchronous data link.

Abstract: Disclosed is a system, method and circuit for mirroring data on a data server. According to some embodiments of the present invention, a primary mirroring module associated with a primary server may be adapted to establish data mirroring connections between the primary server and one or more mirror sever systems. According to some embodiments of the present invention, the primary mirroring module includes an evaluator unit which generates a delta file to be transmitted to the one or more mirror server systems.