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 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 method and a storage system are provided for accessing volumes. The storage system provisions to a host, a place holder handle configured for allowing access to any volume selected by the host and allowed to be accessed by the host. The volume forms part of accessible volumes included in the storage system. The storage system receives from the host a first request for associating the place holder handle with a first selected volume from among the accessible volumes and enables the host to access the first selected volume in response to receiving an access request indicative of the place holder handle.

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: A method for compressing information by a computerized system, the method may include receiving a mixture of DNA data and additional information; and compressing the DNA data to provide compressed DNA data, wherein the compressing comprises encoding the DNA data by using a predefined codeword dictionary that was constructed based upon reference DNA data.

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: The presently disclosed subject matter includes a method and system for enabling the deletion of logical objects characterized by an object identifier (OID). Upon restart following a system interruption, one or more logical objects are identified, each object being addressed by an interrupted delete request. For each identified logical object performing a deletion, the deletion including: reading one or more physical blocks stored in a physical storage space, wherein the one or more physical blocks were linked to the identified logical object before the system interruption, each of the physical blocks includes an OID stored therein indicating a logical object currently linked to the respective physical block; obtaining OIDs stored respectively in the one or more physical blocks; and freeing those physical blocks from among the one or more physical blocks, which store an OID identical to the respective OID of the identified logical object.

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: The presently disclosed subject matter includes a method, system and apparatus, for dynamically controlling resource allocation in a storage system, the storage system comprises at least one storage device and at least one processing unit, the resources being associated with the processing unit. Responsive to a request from a connection for processing data, information in respect of an Allocation state of the processing unit is obtained. The Allocation state is defined as a Limiting Allocation state if the quantity of free resources associated with the processing unit, is lower than a first threshold value. In case the Allocation state of the processing unit is Limiting Allocation state, information in respect of a Connection state of the connection is obtained. The required memory resources are dynamically allocated to the connection according to the current Allocation state of the processing unit and the current Connection state of the connection.

Abstract: A method and a storage system for managing logical objects, wherein the storage system includes a plurality of control servers and the method includes: (i) defining a plurality of object pools and associating each logical object, hosted in the storage system, with one of the plurality of object pools; (ii) configuring each control server to have a primary responsibility over at least two of the object pools, such that each object pool is controlled by one primary control server, configured to handle requests directed to logical objects associated with the object pool; and (iii) in response to a failure of one of the plurality of control servers, configuring each operational server of the plurality of control servers to take over primary responsibility for at least one object pool, originally defined under the primary responsibility of the failed control server.

Abstract: A control layer of a data storage system is configured to identify one or more physical data units in the physical storage, which are associated only with corresponding logical snapshot data units, and to reallocate such physical snapshot data units to a dedicated storage space. The dedicated storage space can be a low-power storage space, which includes one or more disks designated as low power disks. The reallocation of snapshot data units to low power disks can be carried out according to an energy-aware migration policy, directed for minimizing the activation of the low power disks, and maintaining the disks in an inactive state for longer periods of time.

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: According to the teaching disclosed herein there is provided at least a method, system and device for managing a cache memory of a storage system. The storage system is associated with at least one physical storage device and, responsive to a read request, comprising information indicative of a logical address of at least one requested data unit, to obtain a storage physical address associated with the logical address, search the cache memory for a data unit associated with the storage physical address and service the request from the cache in case the data unit is found in the cache memory.

Abstract: A storage system and a method for managing a memory capable of storing metadata related to logical volume sets, are disclosed. A memory quota is assigned to a metadata related to a logical volume set. The size of a memory currently consumed by the metadata is monitored. Upon exceeding a threshold by the size of the monitored memory, at least one restraining action related to memory consumption by the metadata is applied.

Abstract: A method for providing a warranted snapshot that may include: receiving a request to create a first warranted snapshot of a first logical volume at a first point in time and creating the first warranted snapshot if the first warranted snapshot is non-writable and if an amount of physical storage actually devoted by a storage system to the first logical volume at the first point of time does not exceed a size of a free physical storage space that is available for storing any future data delta associated with the first warranted snapshot. The creating of the first warranted snapshot may include allocating a first virtual portion of a physical storage space for storing any future data delta associated with the first warranted snapshot. A size of the first virtual portion equals the amount of physical storage actually devoted to the first logical volume at the first point of time.

Abstract: A system of managing remote resources that includes a local storage associated with a local storage manager constituting a local storage system. A remote storage associated with a remote storage manager constituting a local storage system. The local storage system is associated with a remote storage system by means of a first link. The local storage system is configured to send through the first link I/O remote commands complying with the SCSI protocol, for execution in the remote storage system. The system includes a second link associating the local storage system and the remote storage system. The local storage manager being responsive to remote storage management commands and being configured to send through the second link corresponding cross-storage-remote management commands that comply with the SCSI protocol, for execution in the remote storage.

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: 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 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.