Abstract: A method for contention reduced update of one or more storage system parameters, the method may include (i) concurrently monitoring the one or more storage system parameters (SSPs) by compute entities (CEs); wherein the concurrently monitoring comprises updating, by the CEs, local counters allocated to different SSPs; (ii) updating, by the CEs, sets of shared counter fields with values of the local counters, wherein different sets are allocated to different SSPs; wherein an updating of a set of a shared counter fields by an CE comprises selecting a shared counter field of the set by the CE; and (iii) calculating values of the different SSPs, wherein a calculating of a value of a SSP is based on at least one value of at least one shared counter field of a set that is allocated to the SSP.

Abstract: A method that includes instructing multiple compute entities, by an expansion manager and during a first phase of the stored entity metadata re-balancing, to: lookup any stored entity metadata by using: (a) a current translation function for linking identifiers of stored entities to stored entities metadata; wherein the current translation function is based on a size of a current storage space allocated to stored entities metadata; and (b) a next translation function for linking identifiers of stored entities to stored entities metadata; wherein the next translation function is based on a size of a next storage space allocated to stored entities metadata; wherein the current space is expanded during the expansion of the storage system to provide the next storage space, and to update any stored entity metadata accessed using the current translation function without updating stored entity metadata accessed using the next translation function.

Abstract: A method for recovery point objective compliant star replication, the method includes: obtaining, by a SSS, a user defined RPO value; performing replication iterations to each DSS according to replication schedules of the DSSs, wherein at least two DSSs of the multiple DSSs are assigned with replication schedules having different frequencies of replication iterations; wherein each replication iteration includes sending a content related to a scheduled snapshot; determining a conformance to the RPO, of a time elapsed since a content related to a last common snapshot was replicated to each one of the multiple DSSs; and performing a non-scheduled common (NSC) replication iteration to each of the multiple DSSs to prevent a violation of the RPO, wherein the NSC replication iteration includes sending content related to a NSC snapshot to each one of the multiple DSSs.

Abstract: A method for monitoring largest file system entities of a file system that is stored in a storage system, the method may include populating, during multiple population iterations, a cache of the storage system with largest file system entities metadata; wherein a current population iteration of the multiple population iterations may include pushing, to a heap, metadata related to a set of one or more file system entities that are children of a parent file system entity that was deemed a largest file system entity of a last population iteration that preceded the current population iteration; popping the heap to provide a current largest file system entity; and storing metadata related to the current largest file system entity in the cache.

Abstract: A method for retrieving a file system entity at a presence of snapshot restore in a history of the file system entity , the method may include (i) receiving a request to obtain a content of the file system entity (FSE) at a certain point in time (PIT); and (ii) retrieving the content of the FSE at the certain point in time, wherein the retrieving comprises searching for FSE content segments to be included in a response to the request, wherein each FSE content segment has a write time that does not exceed the certain PIT, each FSE content segment is not included in a relevant blind period of time that is associated with a reversible snapshot restore operation, and fulfills another timing criterion.

Abstract: A method for contention reduced update of one or more storage system parameters, the method may include (i) concurrently monitoring the one or more storage system parameters (SSPs) by compute entities (CEs); wherein the concurrently monitoring comprises updating, by the CEs, local counters allocated to different SSPs; (ii) updating, by the CEs, sets of shared counter fields with values of the local counters, wherein different sets are allocated to different SSPs; wherein an updating of a set of a shared counter fields by an CE comprises selecting a shared counter field of the set by the CE; and (iii) calculating values of the different SSPs, wherein a calculating of a value of a SSP is based on at least one value of at least one shared counter field of a set that is allocated to the SSP.

Abstract: A method for lock metadata re-balancing upon an expansion of a storage system, the method may include instructing multiple compute entities, by an expansion manager and during a first phase of the lock metadata re-balancing, to acquire locks by using: (a) a current translation function for linking addresses of current lock metadata units (LMUs) to identifiers of stored entities; wherein the current translation function is based on a size of a current storage space allocated to the lock metadata; and (b) a next translation function for linking addresses of new LMUs to identifiers of stored entities; wherein the new translation function is based on a size of a new storage space allocated to the lock metadata; wherein the current space is expanded during the expansion of the storage system to provide the next storage space.

Abstract: A method for determining size information related one or more snapshots related to file systems stored in a storage system, the method may include (a) sampling one or more combinations of points in time and logical spaces, the logical spaces are associated with the one or more file systems to provide sampled combinations of sampled portions of file system entities (FSEs) and sampled points in time; (b) searching for relevant snapshots that are relevant to the sampled combinations to provide relevant snapshots at the sampled points in time; and (c) determining physical sizes of the relevant snapshots at the sampled point in time; wherein a number of samples per sampled FSE is indicative of a size of the sampled FSEs.

Abstract: A method for determining size information related one or more file systems stored in a storage system, the method may include (i) sampling one or more logical spaces that are associated with the one or more file systems to provide sampled file system entities (FSEs); wherein a number of samples per sampled FSE is indicative of a size of the sampled FSEs; and (ii) determining logical sizes and physical sizes of different levels of the one or more file systems based on the sampled file system entities.

Abstract: A method for determining size information related one or more snapshots related to file systems stored in a storage system, the method may include (a) sampling one or more combinations of points in time and logical spaces, the logical spaces are associated with the one or more file systems to provide sampled combinations of sampled portions of file system entities (FSEs) and sampled points in time; (b) searching for relevant snapshots that are relevant to the sampled combinations to provide relevant snapshots at the sampled points in time; and (c) determining physical sizes of the relevant snapshots at the sampled point in time; wherein a number of samples per sampled FSE is indicative of a size of the sampled FSEs

Abstract: A method for hierarchical workload allocation in a storage system, the method may include determining to reallocate a compute workload of a current compute core of the storage system; wherein the current compute core is responsible for executing a workload allocation unit that comprises one or more first type shards; and reallocating the compute workload by (a) maintaining the responsibility of the current compute core for executing the workload allocation unit, and (b) reallocating at least one first type shard of the one or more first type shards to a new workload allocation unit that is allocated to a new compute core of new compute cores.

Abstract: A method for maintaining an availability of a storage system, the method may include obtaining, by a control module of the storage system, problem related information generated by one or more compute nodes of the storage system, the problem related information is indicative of one or more problems associated with an execution of one or more storage operations; determining, by the control module and based on the problem related information, whether to forbid an execution of a storage operation of the one of more storage operations; and updating, by the control module, and based on the determining, a forbidden storage operation data structure that is accessible to the compute nodes of the storage system.

Abstract: A method that includes instructing multiple compute entities, by an expansion manager and during a first phase of the stored entity metadata re-balancing, to: lookup any stored entity metadata by using: (a) a current translation function for linking identifiers of stored entities to stored entities metadata; wherein the current translation function is based on a size of a current storage space allocated to stored entities metadata; and (b) a next translation function for linking identifiers of stored entities to stored entities metadata; wherein the next translation function is based on a size of a next storage space allocated to stored entities metadata; wherein the current space is expanded during the expansion of the storage system to provide the next storage space, and to update any stored entity metadata accessed using the current translation function without updating stored entity metadata accessed using the next translation function.

Abstract: A method for lock metadata re-balancing upon an expansion of a storage system, the method may include instructing multiple compute entities, by an expansion manager and during a first phase of the lock metadata re-balancing, to acquire locks by using: (a) a current translation function for linking addresses of current lock metadata units (LMUs) to identifiers of stored entities; wherein the current translation function is based on a size of a current storage space allocated to the lock metadata; and (b) a next translation function for linking addresses of new LMUs to identifiers of stored entities; wherein the new translation function is based on a size of a new storage space allocated to the lock metadata; wherein the current space is expanded during the expansion of the storage system to provide the next storage space.

Abstract: A method for determining a progress of an execution of a task, the method may include accessing only a portion of a shared task status data structure that (a) is associated with the task, wherein the task is executed by a first plurality of compute elements, and (b) comprises multiple hierarchical levels; wherein an entry of a certain hierarchical level represents an aggregate progress associated with multiple entries of the another hierarchical level; the certain hierarchical level is higher than the other hierarchical level; and determining the progress of the execution of the task based on a content of the portion.

Abstract: A method for low-latency data mirroring in a storage system, the method may include receiving, by a compute node of the storage system, a read request for reading a data unit stored at a primary storage block of the storage system; determining, by the compute node and based on primary storage block metadata, whether a content of the primary storage block is consistent; and responding to the determining of whether the content of the primary storage block is consistent. The responding may include (a) when determining that the primary storage block is inconsistent—copying the data unit from the primary storage block to a secondary storage block of the storage system, and updating the primary storage block metadata; and (b) reading the data unit from the primary storage block and sending the data unit to a requesting entity.

Abstract: A method for maintaining an availability of a storage system, the method may include obtaining, by a control module of the storage system, problem related information generated by one or more compute nodes of the storage system, the problem related information is indicative of one or more problems associated with an execution of one or more storage operations; determining, by the control module and based on the problem related information, whether to forbid an execution of a storage operation of the one of more storage operations; and updating, by the control module, and based on the determining, a forbidden storage operation data structure that is accessible to the compute nodes of the storage system.

Abstract: A method for low-latency data mirroring in a storage system, the method may include receiving, by a compute node of the storage system, a read request for reading a data unit stored at a primary storage block of the storage system; determining, by the compute node and based on primary storage block metadata, whether a content of the primary storage block is consistent; and responding to the determining of whether the content of the primary storage block is consistent. The responding may include (a) when determining that the primary storage block is inconsistent—copying the data unit from the primary storage block to a secondary storage block of the storage system, and updating the primary storage block metadata; and (b) reading the data unit from the primary storage block and sending the data unit to a requesting entity.

Abstract: A method for hierarchical workload allocation in a storage system, the method may include determining to reallocate a compute workload of a current compute core of the storage system; wherein the current compute core is responsible for executing a workload allocation unit that comprises one or more first type shards; and reallocating the compute workload by (a) maintaining the responsibility of the current compute core for executing the workload allocation unit, and (b) reallocating at least one first type shard of the one or more first type shards to a new workload allocation unit that is allocated to a new compute core of new compute cores.

Abstract: A system and method for scalable storage. The method includes placing a lock on a portion of a storage node, wherein placing the lock further comprises replacing a first value stored in the storage node with a second value using an atomic operation, wherein the atomic operation replaces the first value with the second value when the first value indicates an empty lock status, wherein the second value indicates an active lock status; allocating a storage location in the storage node by updating metadata stored in the locked portion of the storage node when the lock has been placed; and releasing the lock, wherein releasing the lock further comprises replacing the second value with a third value, wherein the third value indicates the empty lock status.