Abstract: A method for replicating a local storage entity to provide a remote storage entity, the method may include receiving, by a local storage site, after an occurrence of a replication failure, after-failure remote storage site difference information indicative of differences between (i) a certain point in time version of the remote storage entity and (ii) an after-failure point in time version of the remote storage entity; calculating, by the local storage site, after the occurrence of the replication failure, after-failure local storage site difference information indicative of differences between (i) a certain point in time version of the local storage entity and (ii) an after-failure point in time version of the local storage entity; and sending, by the local storage site to the remote storage site, local storage entity portions listed in at least one of the after-failure remote storage site difference information and to the after-failure local storage site difference information, during an after-failure repli

Abstract: A method for controlling multiple replication processes that includes allocating, by a local storage system and for each replication process, local resources for performing local operations that comprise transmitting remote replication content to a remote storage system; the allocating is responsive to a state of transmission of the replication content and a maximal local storage system allocation threshold; allocating, by the remote storage system and for each replication process, remote resources for performing remote operations that comprise handling the replication content transmitted from the local storage system; the allocating is responsive to a load associated with the handling of the replication content, and a maximal remote storage system allocation threshold; and executing each replication process by the replication process local and remote storage systems resources.

Abstract: A method for managing a secondary storage system, the method may include performing a failover update, by the secondary storage system, of a status of at least one secondary path that couples a host computer to the secondary storage system thereby causing the host computer to prioritize sending IO requests to the secondary storage system over sending the IO requests to a primary storage system; wherein the failover update is triggered by a determination made by the secondary storage system that (a) the secondary storage system is, when making the determination, at an acceptable synchronization level with the primary storage system, and (b) the primary storage system is disconnected from the host computer; receiving, from the host computer, IO requests; and responding, by the secondary storage system, to the IO requests.

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 for memory management, the method may include receiving an updated portion of a data unit, the data unit is associated with a logical data entity; wherein the updated portion is smaller than a granularity of a mapping data structure used for retrieval of the data unit; and creating, by the storage system an extended data unit that comprises (i) an original content of the data unit, (ii) the updated portion and, (iii) updated portion metadata; wherein the updated portion metadata comprises (a) updated portion retrieval information for retrieving the updated portion, and (b) updated portion snapshot information indicative of at least one snapshot associated with the updated portion.

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 protecting snapshots related to a logical unit, the method may include retrieving snapshots blocks that were destaged in a storage system; processing, by the storage system, the snapshots blocks to provide, by an information protection module of the storage system, snapshots redundancy information; and storing the snapshots redundancy information in the storage system.

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.

Abstract: A method for managing a cache memory of a storage system, the method may include storing a first retrieval metadata of a first data that is cached in the cache memory, in response to an expected or an actual occurrence of a cache memory consuming event; wherein the cache memory consuming event involves storing second data in the cache memory for a second caching period; replacing, in the cache memory, the first data by the second data; wherein the second caching period is a fraction of a first caching period associated with the first data; and evicting the second data from the cache memory and retrieving the first data to the cache memory in response to an actual or estimated end of the cache memory consuming event; wherein the retrieving of the first data involves retrieving the first data from a storage unit that differs from the cache memory while using the first retrieval metadata.

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 a filesystem by a storage system, the method may include maintaining, by a storage system, a filesystem data structure that comprises filesystem pathnames metadata related to a filesystem that is stored in the storage system; receiving, from a client that is coupled to the storage system via a network, a request to obtain a client filesystem object list related to at least a certain portion of the filesystem; generating, in response to the request and in response to the filesystem data structure, the client filesystem object list, wherein the client filesystem object list comprises at least one pathname of at least one filesystem object that belongs to the at least certain portion of the filesystem; and sending the client filesystem object list to the client.

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 remote storage system. The local storage system is associated with the 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: There is provided a storage system comprising a control layer operable to manage a snapshot family (SF) constituted by SF members having hierarchical relations represented by a SF relationship data structure and a method of operating thereof. Upon receiving a command for restoring a writable SF member from a read-only snapshot thereof, the control layer provides a foreground atomic operation. The atomic operation comprises generating a new writable snapshot of the read-only snapshot (a destination SF member), modifying the SF relationship data structure, and re-assigning all logical unit numbers (LUNs) from the writable SF member to be restored to the destination SF member. Upon successful completion of the atomic operation, the control layer sends acknowledgement indicative of successful restoring the writable SF member.

Abstract: A method for updating a destination volume, the method may include monitoring duplicate traffic that represents original traffic that is exchanged between at least one host computer and a first storage system; wherein the monitoring is executed by a controller during an execution of a migration or a replication of a source volume of the first storage system to a destination volume of a second storage system; wherein the controller is not included in the first storage system; wherein the original traffic is related to the source volume; wherein the duplicate traffic is sent toward the controller by at least one switch that attempts to duplicate the original traffic; and controlling, based upon the monitoring, a process of updating the destination volume with a set of source volume updates, wherein the set of source volume updates are reflected in the duplicate traffic and are received during the execution of the migration.

Abstract: A system and method of operating a filesystem for managing filesystem objects is disclosed. The filesystem objects are characterized by metadata parameters included in a global directory object arranged in a plurality of global directory object (GDO) pages. Responsive to receiving a request for creating a new filesystem object, a parent key is obtained. The parent key is indicative of an identifier of a direct parent directory requested for hosting the new filesystem object. A target page that corresponds to the parent key is located within the plurality of GDO pages. The target page further includes a direct parent directory metadata record associated with the direct parent key and includes metadata parameters related to the direct parent directory. An object key is created as corresponding to the same target page, thereby enabling accommodation of an object metadata record, related to the new filesystem object, on the target page.

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: 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: There is provided a storage system capable to maintain a snapshot family comprising a plurality of members having hierarchical relations therebetween, and a method of operating thereof.

Abstract: There is provided a storage system and a method of identifying delta-data therein between two points-in-time. The method comprises: generating successive snapshots Si and Si+1 corresponding to the two points-in-time; upon generating the snapshot Si+1, searching the cache memory for data blocks associated with snap_version=i, thereby yielding cached delta-metadata; searching the SF mapping data structure for destaged data blocks associated with snap_version=i, thereby yielding destaged delta-metadata; and joining the cached delta-metadata and the destaged delta-metadata, thereby yielding delta-metadata indicative of the delta-data between points-in-time corresponding to the successive snapshots with Snap_ID=i and Snap_ID=i+1. The method operates with no need in copying, destaging to a dedicated location and/or any other special handling of data that needs to be transmitted to the RS system.

Abstract: A storage system that may include a management module; and multiple disk drives; wherein the management module is arranged to allocate disk drives of the multiple disk drives to disk drive groups, each disk drive group corresponds to at least one redundancy array of independent disks (RAID) group of data in response to at least one out of: locations of the disk drives within disk drive enclosures; and expected or actual temperatures of the disk drives.