Abstract: A method for safe storage of a data portion, the method includes (a) receiving, at a storage system, the data portion; (b) selecting, based on at least a timing parameter, a redundancy scheme for safe storage of the data portion; wherein the redundancy scheme is selected out of (i) mirroring the data portion and (ii) applying a stripe based protection on the data portion, at a storage space of the storage system; and (c) safe storing the data portion by applying the selected redundancy scheme.

Abstract: A method for managing metadata blocks of file system entities (FSEs), the method includes (i) determining, by a processing circuit of a storage system, a stress level that is non-linearly dependent upon a fullness of static FSE metadata blocks and a fullness of dynamic FSE metadata blocks, wherein the static FSE metadata blocks store FSE metadata items of a first type and the dynamic FSE metadata blocks store FSE metadata items of a second type and additional FSE metadata items of a first type; (ii) determining, based on the stress level and a fullness parameter, a probability of applying a conditional compression process on a new FSE metadata block; and (iii) applying the conditional compression process, based on the probability, on the new FSE metadata block.

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 updating a partially ordered database, the method includes (a) obtaining, by a merge circuit, density values of multiple sorted table chunks of the partially ordered database, wherein a density value of each sorted table chunk is indicative of a relationship between a number of populated rows of the sorted table chunk and a width of the sorted table chunk, wherein the width of the sorted table chunk is determined based on (i) values of sort keys of the sorted table chunk, and (ii) a parameter of a distribution of values of sort keys of the partially ordered database; each sort key is associated with a row of a table of the partially ordered database and represents values of multiple cells of the row; (b) merging, by the merge circuit, a set of sorted table chunks to provide a new sorted table chunk that exhibits a density value that exceeds a density value of each sorted table chunk of the set; and (c) replacing, in a storage unit of a storage system, the set of sorted table chunks by the new sor

Abstract: A method for cluster based searching for a value range stored in a storage system, the method may include receiving a request to find a certain value range within a set of information elements that are stored in a storage system; wherein the set of information elements comprises subsets of information elements associated with subset hash based filters; wherein different subsets of information elements are associated with different subset hash based filters; determining a certain cluster value of a certain cluster that comprises the certain value range; applying one or more hush functions on the certain cluster value to provide one or more hash results; and determining whether one or more members of the certain cluster are possibly in a subset of information elements, based on the one or more hash results and on a subset hash based filter of the subset of information elements; and when determining that the one or more members of the certain cluster are possibly in the subset then searching, within the subset,

Abstract: A method for managing write buffers (WBs), that includes (i) receiving write requests for writing input information units (IIUs) to the storage system; (ii) estimating an occurrence of a future overflow of first WBs that are allocated, during steady state operation, to store IIUs before the IIUs are processed and migrated to a permanent storage; and (iii) responding to the estimating by (a) storing at least some IIUs at second WBs without temporarily storing the at least some of the IIUs in the first WBs; (b) reducing a rate of a migration of IIUs from the first WBs and the second WBs to the permanent storage; and (c) introducing intentional delays in handling an ingestion of one or more newly received write requests.

Abstract: A method for transaction conflict management, the method includes writing, by a transaction controller and to a given logical address within a logical address space supported by a storage system, defragmentation data related to a defragmentation process, the defragmentation data being overwritable; identifying, by transaction controller, a transaction conflict associated with the defragmentation process, and (b) one or more user transaction requests related to the given logical address; and resolving the transaction conflict based on (i) the defragmentation data being overwritable, (ii) a timing of the writing of the defragmentation data, and (iii) one or more timings of one or more user transaction operations in relation to the one or more user transaction requests.

Abstract: A method for splitting a node of a metadata tree, the method includes (i) splitting the node of the metadata tree based on a lock contention parameter that differs from a fullness of the node, to provide split nodes; and (ii) preventing a size based merge of the split nodes for a time period following a period of a defined duration that starts after the splitting.

Abstract: A method for time-aligning data sent from a first storage system to a second storage system, the method includes (i) receiving multiple data units and a synchronization message, by a controller of the second storage system (SSS) and while applying a synchronous replication scheme; the multiple data units comprise first snapshot (S1) data units and second snapshot (S2) data units; the synchronization message indicates that a controller of the FSS has changed an allocation of data units from the S1 to the S2; and (ii) associating SSS timestamps with the multiple data units, wherein the associating of the SSS timestamps includes (a) associating a SSS timestamp related to the S1 for each S1 data unit, regardless a timing relationship between a time of reception of the synchronization message and a time of reception of the S1 data unit; and (b) delaying an association of a SSS timestamp related to the S2 for each S2 data unit, until receiving the synchronization message.

Abstract: A method for locking metadata, the method includes (i) executing a first FSE command, by obtaining a lock of FSE metadata that is related to the FSE and is stored at a remote shared storage unit, and creating and accessing a local version of the FSE metadata; (ii) estimating that a reception of the first FSE command will be followed, within a defined time frame, by a reception of a second FSE command; (iii) maintaining the lock following a completion of the first FSE command; and (iv) executing the second FSE command, following the reception of the second FSE command, wherein the executing of the second FSE command includes accessing the local version of the FSE metadata.

Abstract: A method for managing file system entity (FSE) open requests in a shared namespace. According to an embodiment, the method includes (a) receiving, by a controller of a first storage system (FSS), a second storage system (SSS) transfer request for transferring to the SSS a responsibility to manage SSS given FSE open requests, the SSS given FSE open requests are generated by SSS users; (b) determining, by the controller of the FSS, whether to grant the SSS transfer request, wherein the determining is based on whether there is a current granted given FSE open request. When it is determined to grant the SSS transfer request the method includes (c) transferring the responsibility to manage the SSS given FSE related open requests to the SSS; and (d) updating, by the controller of the FSS, a FSS transfer data structure to reflect the transferring of the responsibility.

Abstract: A method for metadata blocks access, the method includes (i) accessing, following a reception of an access request, a metadata block related to a file system entity; the metadata block is associated with a transaction identifier that is indicative of a transaction that is a most recent transaction that modified the metadata block; (ii) traversing, starting from the metadata block, metadata blocks that are transaction related, using linkage metadata within the metadata blocks; (iii) determining, based on an outcome of the traversing, a status of the transaction; (iv) when it is determined that the transaction was successfully completed then completing the access request by using content that was written by the transaction to the metadata block; and (v) when it is determined that the transaction failed then ignoring content that was written by the transaction to the metadata block.

Abstract: A method for asynchronous replication, the method includes initiating a current replication cycle of multiple files system entities (FSEs) that include primary FESs originated from a primary storage system (PSS) and external FSEs that originated from one or more external storage systems (ESSs), each external storage system differs from the primary storage system and differs from a secondary storage system. The initiating is followed by sending primary content and external content from the primary storage system to the secondary storage system. The primary content is indicative of differences in the primary FSEs between a previous replication cycle point in time (PIT) and a current replication cycle PIT.

Abstract: A method for user-defined validation of content stored in a storage system, the method may include receiving a request to execute a user-defined validation process (UDVP) on the content that is stored in the storage system; wherein the request is associated with means for executing the UDVP, and a content identifier; scheduling, by the storage system, at least one execution of the UDVP; executing the UDVP according to the scheduling to provide one or more validation results; and finding that the one or more validation results are indicative of potential security issues and performing one or more validation-triggered security measures.

Abstract: A method for managing lost content change requests (CCRs), the method includes (i) maintaining, by compute entities of a second storage system (SSS), states of executions of multiple CCRs of multiple categories and of multiple SSS reception times; (ii) receiving, from a first storage system (FSS), at a failure indication reception time (FIRT), a failure indication that is indicative of a certain category of the multiple categories. The certain category is associated with a failure of the FSS to receive a response, from the SSS, to a certain CCR of the certain category, that was presumably sent from the FSS to the SSS; (iii) determining, based on states of executions that are related at least to the certain category, when the SSS has completed to execute all CCRs of at least the certain category that were received by the SSS up to the FIRT; and (iv) transmitting, by the SSS, a SSS completion indication that indicates that the SSS has completed to execute all tasks that were received by the SSS up to the FIRT.

Abstract: A method for writing data to a shared write buffer, the method includes (i) receiving, by a processing circuit of a compute node of a storage system, a write request for writing to the shared write buffer an information unit associated with an accessing entity located outside the storage system; wherein the shared write buffer is stored in a non-volatile memory of a storage node of the storage system; the storage node is in communication with the compute node; (ii) determining, by the processing circuit whether to (a) store the information unit in a non-shared segment of the shared write buffer, or (b) store the information unit in a shared segment of the shared write buffer while applying a locking mechanism; wherein the determining is based on parameters, the parameters include a writing parameter of the accessing entity, a writing latency parameter associated with the accessing entity, and a locking timing parameter; and (iii) storing the information unit according to the determination.

Abstract: A method for responding to a query, the method may include (a) receiving, by a storage system compute element, a query that comprises one or more conditions related to a content of at least one data unit (DU); (b) searching, based on the one or more conditions and on a condition fulfillment information (CFI), for one or more irrelevant groups of DUs to be skipped during the responding to the query; wherein the one or more irrelevant groups of DUs belong to multiple stored groups of DUs that are stored in the storage system; wherein an irrelevant group of DU does not comprise, according to the CFI, any DU that fulfills the one or more conditions; and (c) generating a response to the query based on an outcome of the searching.

Abstract: A method for compression of cells of a tabular database (TD), the method may include (i) receiving data elements, by a storage system; (ii) calculating a compressed representation (CR) of the data elements by applying a compression process that includes (ii.a) defining sets based on data element values, (ii.b) associating a set value per set; and (ii.c) generating the CR of the data elements based on differences between the data elements and corresponding set values; (iii) generating compression metadata related to the CR of the data elements, wherein the compression metadata comprises the set values and a mapping between the CR of the data elements and the set values; and (iv) storing, in the TD, the CR of the data elements.

Abstract: A method for managing tasks in a storage system, the method may include: (a) obtaining, by a scheduler, a shared budget for background storage tasks and foreground storage tasks; (b) obtaining, by the scheduler, a background budget for background storage tasks; wherein the background budget is a fraction of the shared budget; (c) allocating, by the scheduler, resources to pending storage tasks according to the shared budget and the background budget; wherein the allocating comprises (i) allocating the shared budget while prioritizing foreground storage tasks over background storage tasks; and (ii) allocating the background budget to background storage tasks; and (d) participating, by the scheduler, in executing of storage tasks according to the allocation.

Abstract: A method for transitioning from asynchronous replication to a synchronous replication, the method includes (i) receiving, by a DSS and following the start of the transitioning, a synchronous update related to a first FSE part; (ii) implementing the synchronous update of the first FSE part; (iii) receiving, by the DSS and following the start of the transitioning, an asynchronous update related to a last version of a second FSE part before the start of the transitioning; (iv) ignoring the asynchronous update when the DSS currently stores a version of the second FSE part that is associated with a timestamp that is indicative of a point in time that exceeds the start of the transitioning; and (v) else—implementing the asynchronous update.