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 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: 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 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: According to the presently disclosed subject matter there is provided, inter alia, a system and method which enable to identify, in a storage-system, malfunctioning disks, and in response, to activate a power-cycle process only for the specific failing disks, in order to bring these disks into proper operational mode. During the power-cycle process of a failing disk, other disks, which are not failing, remain operative and available.

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: A method and system is disclosed for storage optimization of thin provisioning. Non-zero data units within data portions are re-allocated to specifically designated one or more areas in the physical storage space and the physical address of the non-zero data unit within the designated area is associated with the logical address of the non-zero data unit. In case the data portion is allocated to the physical storage, the physical storage space initially allocated to the data portion is returned to the pool of available physical storage space, thereby freeing the storage space for storing other data.

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: 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: According to the presently disclosed subject matter there is provided inter alia, a method and system which enable to uncover errors which are correctible by a data integrity mechanism in a computer system. The same data is read with the help of two different types of read commands. The first command is a read command which does not implement an inherent ECC and therefore does not correct corrupted data. The second command is a read command which includes an ECC and is adapted to correct errors which are detected in the data which is being read. The data obtained by each of the two read commands is compared, and in cases where a difference is identified between the two data, it is determined that an error has been detected and corrected by the ECC.

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: 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.

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 available to said hosts and characterized by an Internal Virtual Address Space (IVAS); a second virtual layer characterized by a Physical Virtual Address Space (PVAS), interfacing with the physical storage devices, and operable to represent an available storage space; and an allocation module operatively coupled to the first and second virtual layers and providing mapping between IVAP and PVAS. Each address in PVAS is configured to have a corresponding address in IVAS. The allocation module facilitates management of IVAS and PVAS, enabling separation of a process of deleting certain logical object into processes performing changes in IVAS and PVAS, respectively.

Abstract: A method for a takeover in a case of a failure of a server in a storage system includes: a) configuring each virtual partition (VP) to be controlled by a primary data server and a secondary data server b) configuring each data server to have primary responsibility over all logical block addresses (LBAs) corresponding to at least two virtual partitions and to have secondary responsibility over all LBAs corresponding to at least two other virtual partitions; c) responsive to a failure of a data server, i) re-configuring primary responsibility over each VP previously primary controlled by the failed server such that it becomes primary controlled by a server previously configured as a secondary server with respect to this VP; and ii) re-allocating secondary responsibility over each VP previously secondary controlled by the failed server in a manner that each such VP becomes secondary controlled by a server other than the newly assigned server with primary responsibility.

Abstract: There are provided a mass storage system and a method of operating thereof. The method comprises: a) dividing the storage space into a first portion configured to be available to a client and a second portion configured to be unavailable to a client, thus giving rise, respectively to an available storage space and a spare storage space; b) distributing the available space and the spare space over the disk drives thus giving rise to available space and spare space allocated to each given disk drive; c) detecting underperformance of at least one disk drive among the plurality of disk drives; d) responsive to detecting underperformance, decreasing respective available space allocated to said at least one underperforming disk drive and respectively increasing spare space allocated to said at least one underperforming disk drive thus giving rise to a re-configured allocation of the available space; and e) transferring the stored data in accordance with said re-configured allocation of the available space.