Abstract: There is provided a storage arrangement and a method of operating thereof. The storage arrangement comprises a first storage system and one or more second storage systems operatively coupled to the first storage system. First control layer is operable to handle a first logical address space comprising a first logical group characterized by a plurality of logical block addresses; first control layer comprises a first mapping module handling a first mapping structure associated with first logical group. Each second control layer comprises, respectively, a second mapping module handling a second mapping structure associated with first logical group.

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: 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: There is provided a method of operating a multipath storage system, the method comprises: identifying a primary storage control port configured to be responsible for a given LBA range and a secondary storage control port configured to have secondary responsibility for the given LBA range; reducing, in a manner unaffecting respective inbound I/O operation, outbound I/O operation related to the given LBA range and occurring at the primary storage control port, thereby causing a situation requiring switching all respective I/O requests to an alternating path; analyzing responsive changes in outbound I/O operation related to the given LBA range and occurring at the secondary storage control port, and verifying operability of switching to the alternating path in accordance with the obtained results.

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: Storage systems with reduced energy consumption, methods of operating thereof, corresponding computer program products and corresponding program storage devices. Some non-limiting examples of a write method include: configuring a plurality of storage disk units such that at any given point in time there are at least two storage disk drives operating in active state in any storage disk unit; caching in a cache memory one or more write requests and generating a consolidated write request corresponding to a stripe in a RAID group; destaging the consolidated write request; and writing the destaged consolidated write request in a write out of place manner to one or more storage disk drives operating at the destage point of time in active state.

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: There is provided a storage system and a method of migrating a source data portion from a source logical volume to a destination range in a destination logical volume. The method comprises: configuring a source mapping data structure to comprise an entry associated with said source data portion and indicative of mapping between logical addresses corresponding to said source data portion and addresses corresponding to said source data portion and related to a physical address space; and, responsive to a migration command, 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, said entry in the source mapping data structure to be used for mapping to said addresses related to said physical address space and corresponding to the source data portion and to the migrated data portion.

Abstract: There are provides an allocation module and a method of allocating a logical disk to a next member of a given RAID group. The method comprises: identifying one or more physical disks comprising at least one logical disk with already allocated member of said given RAID group, thus giving rise to allocated physical disks; identifying one or more pairs constituted by at least one allocated physical disk with non-allocated physical disks, said pairs having minimal number of RAID groups with members allocated to both physical disks in the pair, thus giving rise to a first group of pairs with minimal contention value; and selecting among the first group of pairs with minimal contention value one or more non-allocated physical disks as candidate physical disks for allocating said next member MEMi+1 of said given RAID group, wherein 0<i<N+1.

Abstract: A storage system and method is provided including physical storage devices controlled by storage control devices constituting a storage control layer operatively coupled to the physical storage devices and hosts. The storage control layer includes: a first virtual layer interfacing with the hosts, operable to represent a logical address space characterized by logical block addresses and available to said hosts and characterized by an Internal Virtual Address Space (IVAS) and operable, responsive to a configuration or I/O request addressed to the logical block addresses, to translate said logical block addresses into IVAS addresses; and a second virtual layer interfacing with the physical storage devices, operable to represent an available physical space to said hosts and characterized by a Physical Virtual Address Space (PVAS), addresses in PVAS having corresponding address in IVAS. The second virtual layer is operable to translate said respective IVAS addresses into addresses in the physical address space.

Abstract: A method of operating a storage system includes: configuring the address space so that each LBA is assigned to at least two servers among a plurality of at least three servers in a control grid: to a primary server with a primary responsibility for handling requests corresponding to said LBA, and to a secondary server with a secondary responsibility for handling requests corresponding to said LBA. In response to a request corresponding to a certain LBA range, generating by a data server having primary responsibility over the certain LBA range, a primary cache object; identifying a data server configured as a secondary data server with regard to the certain LBA range; and generating a redundancy cache object corresponding to the primary cache object only at the identified secondary data server, the redundancy cache object to be used by the identified secondary data server when taking the primary responsibility.

Abstract: In accordance with certain aspects of the presently disclosed subject matter, there is provided a storage system and a method of storing data thereof. The method comprises: storing a plurality of snapshots of a certain source; assessing to at least one given snapshot an assessed value characterized by at least one of the following values and/or derivatives thereof: i. a first value characterizing the amount of unique physical data blocks associated, merely, with said given snapshot; ii. a second value characterizing the amount of unique physical blocks associated merely with a certain group of snapshots comprising said given snapshot; iii a combination of the first and the second value; and updating the assessed value responsive to a pre-defined event.

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 is provided a storage arrangement and a method of operating thereof. The storage arrangement comprises a first storage system and one or more second storage systems operatively coupled to the first storage system. First control layer is operable to handle a first logical address space comprising a first logical group characterized by a plurality of logical block addresses; first control layer comprises a first mapping module handling a first mapping structure associated with first logical group. Each second control layer comprises, respectively, a second mapping module handling a second mapping structure associated with first logical group.

Abstract: A method of migrating data from a source storage resource to a destination storage resource involves selecting a source volume in the source storage resource; configuring in the destination storage resource a destination volume corresponding to the source volume and having the same properties; and redirecting I/O requests from an application running on a host to the destination volume instead of the source volume, whilst migrating data stored in the source volume to the destination volume. A storage system is operable as a destination storage system for migrating data from a source storage system, including means for configuring a destination volume corresponding to a source volume in the source storage system and a migration module having a non-transitory computer useable medium and operable to initiate read requests addressed to the source volume thereby enabling a background process of migrating data stored in the source volume to the destination volume.

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 method of operating a storage system includes: configuring the address space so that each LBA is assigned to at least two servers among a plurality of at least three servers in a control grid: to a primary server with a primary responsibility for handling requests corresponding to said LBA, and to a secondary server with a secondary responsibility for handling requests corresponding to said LBA. In response to a request corresponding to a certain LBA range, generating by a data server having primary responsibility over the certain LBA range, a primary cache object; identifying a data server configured as a secondary data server with regard to the certain LBA range; and generating a redundancy cache object corresponding to the primary cache object only at the identified secondary data server, the redundancy cache object to be used by the identified secondary data server when taking the primary responsibility.

Abstract: A storage system and method are provided including physical storage devices controlled by storage control devices constituting a storage control layer operatively coupled to the physical storage devices and hosts. The storage control layer includes: a first virtual layer interfacing with the hosts, operable to represent a logical address space characterized by logical block addresses, characterized by an Internal Virtual Address Space (IVAS) and operable, responsive to I/O requests addressed to logical block addresses, to provide protocol-dependent translation of said logical block addresses into IVAS addresses; and a second virtual layer interfacing with the physical storage space, and operable to represent available physical space to said hosts and characterized by a Physical Virtual Address Space (PVAS). Each address in PVAS having a corresponding address in IVAS.