Abstract: There is provided a storage system comprising a control layer operable to manage a plurality of snapshot families, each family constituted by snapshot family members having hierarchical relations therebetween. The method of operating the storage system comprises searching a cache memory for an addressed data block corresponding to an addressed LBA and associated with an addressed snapshot family and an addressed SF member. In a case of missing the addressed data block in the cache memory, identifying in the cache memory all dirty data blocks corresponding to the addressed LBA and associated with the addressed snapshot family (candidate data blocks); identifying among SF members of the addressed snapshot family a destage owner, and in a case when the identified destage owner is associated with a candidate data block, reading from the cache memory such candidate data block.

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 hash-based writing, the method comprises: receiving a received data entity to be stored in a storage system, wherein the received data entity is associated with received data entity metadata; selecting a selected data structure out of a set of data structures that comprises K data structures; wherein K is a positive integer; wherein for each value of a variable k that ranges between 2 and K, stored data entity metadata that is stored in a k'th data structure out of the set collided with stored data entity metadata that is stored in each one of a first till (k?1)'th data structures of the set; calculating an index by applying, on the received data entity metadata, a hash function that is associated with the selected data structure; determining whether an entry that is associated with the index and belongs to the selected data structure is empty; writing to the entry, if the entry is empty, the received data entity metadata, and storing the received data entity in the storage system in response to

Abstract: A method for de-duplication, the method may include receiving a request to store in a storage system a received data entity; obtaining a received data entity signature that is responsive to the received data entity; selecting a selected data structure out of a set of data structures that comprises K data structures; wherein K is a positive integer; wherein for each value of a variable k that ranges between 2 and K, a stored data entity signature that is stored in a k'th data structure out of the set collided with stored data entity signatures that are stored in each one of a first till (k?1)'th data structures of the set; calculating an index by applying, on the received data entity signature, a hash function that is associated with the selected data structure; determining whether an entry that is associated with the index and belongs to the selected data structure is empty; writing to the entry, if the entry is empty, the received data entity signature, and storing the received data entity in the storage sys

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 for managing data includes providing at least one logical device having a table of information that maps sections of the logical device to sections of at least two storage areas. Characteristics of data associated with at least one section of the logical device may be evaluated. The at least one section of the data may moved between the at least two storage areas according to a policy and based on the characteristics of the data. The table of information is updated according to the movement of data between the at least two storage areas.

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 that may include calculating multiple set parity units for multiple sets of data units that are cached in a storage system thereby providing 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 exceeds the first number. Destaging the group of units and the at least one group parity unit to multiple disks of the storage system.

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 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: 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 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: A method for managing read requests, the method may include receiving from a requesting entity a read request for reading an information unit stored in a storage system; determining by a control entity of the storage system whether the information unit is cached in a cache memory of the storage system and whether at least a predetermined number of disk drives of the storage system are currently overloaded; introducing a delay to a response to the read request thereby increasing a time difference between a time of the receiving of the read request and a time of a provision of the information unit to the requesting entity, if it is determined that the information unit is not cached in the cache memory and that the at least predetermined number of disk drives of the storage system are currently overloaded; and providing the information unit to the requesting entity.

Abstract: A storage system that may include a management module, a communication module and a storage module; wherein the management module is arranged to receive, at an intermediate point in time that occurs between the first point in time and a second point in time, a first request that indicates that a certain extent of the second logical volume is irrelevant; participate in a creation of second point in time snapshots of the first and second logical volumes; select, in response to the first request, out of all data deltas generated between the first and second point in time, selected data deltas to be transmitted to the other storage system; wherein the selected data deltas exclude data deltas associated with the certain extent that were generated between the first point in time and the intermediate point in time.

Abstract: The presently disclosed subject matter includes, inter alia, a storage system and a method of managing allocation of data in case an enclosure in a storage system becomes unavailable. The storage system has a storage space configured as a plurality of RAID groups, each RAID group comprising N parity members. According to one aspect of the disclosed subject matter, responsive to a write request, at least one section allocated to a disk in an unavailable enclosure is identified; at least one temporary RAID group in a spare storage space of the storage system is allocated and data related to the write request is written to the alternative RAID group.

Abstract: There are provided a storage system and a method of operating thereof. The method comprises: a) representing to a plurality of hosts an available logical address space divided into one or more logical groups (e.g. logical volumes, virtual partitions, snapshots, combinations of a given logical volume and its respective snapshot(s), etc.), and b) mapping between one or more contiguous ranges of addresses related to the logical address space and one or more contiguous ranges of addresses related to the physical address space, wherein said mapping is provided with the help of one or more mapping trees, each tree assigned to a separate logical group in the logical address space.

Abstract: A method for generating transaction aware snapshots, the method may include: (a) starting a creation of a certain point in time snapshot for a consistency group that comprises at least one logical volume; (b) detecting that at the certain point in time there is an uncompleted transaction for writing multiple information units to the consistency group; the uncompleted transaction started at a transaction start point in time that precedes the certain point in time; (c) preventing an access to the certain point in time snapshot until a completion of the uncompleted transaction; and (d) associating the multiple information units with at least the certain point in time snapshot.