Abstract: A method for maintaining consistency among metadata elements (MDEs) of a logical object, includes: configuring a child MDE to include a correlation value uniquely indicative of a parent MDE. The parent MDE includes a reference to the child MDE; determining an order of performing at least two write operations included in a transaction related to the logical object: at least one write operation with respect to the parent MDE and at least one write operation with respect to the child MDE; the determined order assures that the child MDE is indicated as existing and includes the first correlation value, as long as the parent MDE exists; upon a first access to the parent MDE, subsequent to the transaction, verifying consistency between the parent MDE and the child MDE, using the first correlation value; and deleting the parent MDE if the verifying of consistency is unsuccessful.

Abstract: A method for managing physical resources of a storage system, the method may include transmitting, to a remote site, first information representative of a first snapshot of a logical entity; wherein the first snapshot is associated with first data that is stored in first physical addresses of the storage system; wherein the first physical addresses are mapped to first logical addresses; receiving from the remote site a first acknowledgment indicating that the first information was fully received by the remote site; and disassociating, in response to a reception of the first acknowledgement, the first snapshot from the first physical addresses while maintaining a logical association between the first snapshot and the first logical addresses.

Abstract: A method that includes calculating multiple set parity units for multiple sets of data units that are cached in a storage system thereby providing a group of units that includes multiple sets of units. Each set of units includes a set of data units and at least one associated set parity unit that facilitate a reconstruction of the set of units when a first number of units of the set of units is lost. Calculating at least one group parity unit for the group of units. A combination of the at least one group parity unit and at least one associated set parity unit facilitate a reconstruction of the set of units upon a failure of a second number of units of the set of units. The second number of units of the set of units exceeds the first number of units of the set of units. Destaging the group of units and the at least one group parity unit to multiple disks of the storage system.

Abstract: A method for pre-fetching information units, the method may include: (I) Receiving, by a storage system, write requests for writing information units to the storage system. Each write request includes a first identifier and a second identifier. The first identifier identifies a logical address. A combination of the first and second identifiers identifies an accessing entity that initiated the write request. (II) Receiving a read request for reading at least one information unit from the storage system, the read request is initiated by a certain accessing entity. (III) Determining whether to perform a pre-fetch of at least one additional information unit in response to at least one write request that was initiated by the certain accessing entity. If is determined to perform the pre-fetch then fetching the at least one additional information unit.

Abstract: There is provided a storage system and a method of moving a source data portion from a source logical volume to a destination logical volume. The method comprises: configuring a source mapping data structure to comprise an entry indicative of mapping between logical addresses corresponding to source data portion and addresses corresponding to source data portion and related to a physical address space; and, responsive to a move command, providing an atomic operation comprising configuring a destination mapping data structure to comprise an entry associated with said at least one destination range and comprising a reference to said entry in the source mapping data structure; and configuring said at least one entry in the source mapping data structure DSsrc to bear an indication that said one or more contiguous ranges of addresses corresponding to said source data portion in the source logical volume Vsrc are unavailable to a client.

Abstract: A storage system, a non-transitory computer readable medium and a method of pre-fetching. The method may include determining, by a pre-fetch module of the storage system, to fetch a certain data portion from a data storage device of the storage system to a cache memory of the storage system; wherein the certain data portion belongs to a certain statistical segment that belongs to at least one logical volume; determining, by a pre-fetch module of the storage system, to pre-fetch at least one additional data portion to the cache memory based upon input/output (I/O) activity statistics associated with the certain statistical segment; wherein the I/O activity statistics comprises timing information related to I/O activities; fetching the certain data portion; and pre-fetching the at least one additional data portion if it is determined to pre-fetch the at least one additional data portions.

Abstract: There is provided a storage control grid capable of controlling at least one service provided in the storage system and a method of operating thereof. The storage control grid comprises at least one service dispatcher operatively coupled to at least one service requestor and to a plurality of service providers. The method comprises requesting by service requester a service, thus giving rise to at least one service request; enabling, using said at least one service dispatcher, delivery of the service request to at least one service provider among said plurality of service providers, said service provider configured to provide said at least one service, wherein the delivery is enabled in accordance with data comprised in a service data structure handled by said at least one service dispatcher and indicative, at least, of association between said at least one service and service providers among said plurality of service providers.

Abstract: A system and method that include configuring local disk drives of a local storage system so that at any given point of time, a first part of the local disk drives operate in a low power state and a second part of the local disk drives operate in an active state; and in response to a read request of a data portion on a local disk drive of the local disk drives: determining whether the local disk drive currently operates in the low power state; reading the data portion from the local disk drive, if the local disk drive does not currently operate in the low power state; if the local disk drive currently operates in the low power state, enquiring if a remote mirror disk drive that stores a copy of the data portion currently operates in the low power state; wherein the remote mirror disk drive is comprised in a remote storage system that is coupled to the local storage system; and if the remote mirror disk drive does not currently operate in the low power state, requesting from the remote storage system to read th

Abstract: The presently disclosed subject relates at least to a method and system for controlling access to a logical unit (LU) in a logical storage space, available to a given initiator, representing a corresponding physical storage space, said logical storage space being accessible via a storage control layer, said storage control layer being associated with a security manager. A first value is generated by the security manager, based on a secret key, and transmitted to host requesting permission to access the logical storage space, while the secret key is made available to a target associated with the logical storage space. The host sends to the control device an access related request, the request comprising a second value which was generated based on the first value. Responsive to the command the target calculates the first value, based on the secret key and the second value based on the first value.

Abstract: A method for a snapshot family based reading of data units from a storage system, the method comprises: receiving a read request for reading a requested data entity, searching in a cache memory of the storage system for a matching cached data entity, if not finding the matching cached data entity then: searching for one or more relevant data entity candidates stored in the storage system; selecting, out of the one or more relevant data entity candidates, a selected relevant data entity that has a content that has a highest probability, out of contents of the one or more relevant data entity candidates, to be equal to the content of the requested data entity; and responding to the read request by sending the selected relevant data entity.

Abstract: A method for responding to an extent change operation, the method may include receiving, by a storage system and from a requesting entity, a request to perform an extent content change operation that involves changing a content of a certain extent within a logical space supported by a storage system; generating, in response to the request, extent change operation information that comprises (a) an event counter indicative of a time of requested occurrence of the extent change operation, (ii) a type of extent change operation indicator, and (ii) logical addresses associated with the extent change operation; and sending to the requesting entity an acknowledgement indicative of a completion of the extent change operation before a completion of the extent change operation if an expected content of the certain extent is known before completion of the extent change operation.

Abstract: Storage system(s) for storing data in physical storage in a recurring manner, method(s) of operating thereof, and corresponding computer program product(s).

Abstract: A storage system that includes a management communication interface coupled to a storage management layer and further includes a data communication interface. Upon receiving a request for accessing the storage management layer, from the host, via the data communication interface, the management layer sends to the host, access information necessary for allowing access of the host to the storage management layer via the management communication interface; and upon receiving a management command, from the host via the management communication interface, the host is provided with access to the storage management layer, in cases where the management command conforms to the access information.

Abstract: A request for obtaining a space allocation descriptor is received by a block control layer of a storage system. The space allocation descriptor is indicative of one or more logical blocks free for allocation within a range of logical addresses. The range of logical addresses is included within a logical address space related to an upper layer application which has issued the request. The space allocation descriptor is provided by using a data structure included in the block control layer and operative to map between the logical address space and allocated storage blocks within a physical storage space, managed by the block control layer.

Abstract: A storage system that includes multiple nodes, each node comprises a SSD cache and a management module and hard disk drives that are coupled to the nodes. The management module of each node is arranged to manage a SSD cache map that comprises multiple entries for storing mappings from logical addresses to SSD cache physical addresses and to physical addresses in the hard disk drives. The mappings are related to data units stored in the SSD cache. Upon a rejoin of a certain node following a shut-down or a failure of the certain node, the certain node is arranged to: obtain from at least one other node, current mappings between logical addresses and physical addresses in the hard disk drives, and perform a validation process of the data units stored in the SSD cache in response to relationships between the current mappings and the entries of the SSD cache map.

Abstract: A method for disk failure protection, the method may include calculating a first set of parity units by processing a first group of sets of data units that are cached in a cache memory of a storage system; calculating a second set of parity units by processing the first group of sets of data units; wherein the calculating of the second set of parity units is responsive to a first shift that was virtually introduced between each set of data units of the first group of sets of data units; and destaging the first group of sets of data units and the first and second sets of parity units to the first group of disks.

Abstract: According to an embodiment of the invention there may be provided a method for multi-level disk failure protection, the method may include: calculating first parity information by processing a first data entity that is cached in a cache memory of a storage system thereby providing a first level of disk failure protection; destaging the first data entity and the first parity information to first physical addresses mapped to multiple disks; calculating extra parity information by processing the first data entity, wherein a combination of the first and extra parity information provides an extra level of disk failure protection that exceeds the first level of disk failure protection; and destaging the extra parity information to at least one second physical address that differ from the first physical addresses, the at least one second physical address are included in a spare physical memory space that is not allocated, at a time of the destaging of the extra parity information, for storing data.

Abstract: A method for managing physical resources of a storage system, the method may include transmitting, to a remote site, first information representative of a first snapshot of a logical entity; wherein the first snapshot is associated with first data that is stored in first physical addresses of the storage system; wherein the first physical addresses are mapped to first logical addresses; receiving from the remote site a first acknowledgment indicating that the first information was fully received by the remote site; and disassociating, in response to a reception of the first acknowledgement, the first snapshot from the first physical addresses while maintaining a logical association between the first snapshot and the first logical addresses.

Abstract: A method for generating remote replicates of a logical volume at a remote site, the method comprises performing a plurality of replication cycles for generating a plurality (N) of points in time replicates of the logical volume at the remote site. Wherein for each positive integer n that ranges between 2 and N, a performing of a n'th replication cycle comprises: calculating in parallel and by multiple computerized resources of a storage system, multiple n'th point in time differences of multiple subsets of the logical volume; wherein n'th point in time differences of different subsets are calculated by different computerized resources; wherein a n'th point in time difference of a subset is a difference between an (n?1)'th point in time content of the subset and an n'th point in time content of the subset; and sending, in parallel, the multiple n'th point in time differences to the remote site.

Abstract: A method for performing a comparison between first and second points in time snapshots of a file system entity, the method may include: (I) receiving by a storage system a command that was sent from a host computer, the command is network file system protocol compliant, wherein the command comprises (i) an operation code, and (ii) information about a virtual path, the virtual path that comprises (ii.a) first fields that comprise snapshot comparison parameters indicative of the first and second points in time snapshots of the file system entity, and (ii.