Vast Data Ltd.

Reduxio Systems Ltd.

Other

Avi Goren

Asaf Levy

Yogev Vaknin

Renen Hallak

Oded Sonin

Vladimir Zdornov

Alex Turin

Vlad Zdornov

Ido Yellin

Ohad Ben-Yehuda

Asaf Weissman

Ohad Shamir

Oren Ashkenazi

Guy Keren

Ilan Steinberg

Ori Mamluk

Amir Miron

Shachar Fienblit

Eyal Gordon

Hillel Costeff

Alon Horev

Uri Weissbrem

Ilan Ben-Hagai

Hadar Hen-Zion

Asaf Weisman

Ido Yelin

Ben Danon

Dror Dayan

Lior Shetrit

Evgeny Katz

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.

Managing file system entity open requests

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.

Lost write responses

A method for responding to an access request from a user, the method includes (a) receiving, by a target storage system (TSS) and from a user an access request to access an exposed file system entity (EFSE), the access request is associated with an EFSE external identifier (EEID); (b) applying a logically reversible function on the EEID and on a replication stream identifier (RSID) to provide a TSS internal EFSE identifier (TID); wherein the EFSE was sent to the TSS in association with a replication stream that is identified by the RSID; (c) accessing the EFSE using the TID; and (d) wherein the TID uniquely identifies the EFSE within the TSS.

Managing identifiers of exposed filesystem entities

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.

Asynchronous to synchronous replication transition

A method for updating file system entity (FSE) metadata. The method may include receiving, by a first computing entity, a request to perform a case-sensitive FSE operation that comprises one of (a) adding a case-sensitive version of a name of a FSE to a data structure, or (b) deleting the case-sensitive version of the name of the FSE from the data structure, the data structure comprises multiple name blocks; finding, by the first computing entity, a certain name block of the multiple name blocks that is associated with the case-sensitive version of the name of the FSE. The method may also include determining, by the first computing entity, whether (a) the certain name block is associated with a case-insensitive version of the name of the FSE, and whether (b) the first computing entity preceded a second computing entity in reaching the certain name block, the second computing entity was requested to perform a case-insensitive FSE operation that corresponds to the case-sensitive FSE operation; when it is found that (a) the certain name block is associated with the case-insensitive version of the name of the FSE, and (b) the first computing entity preceded the second computing entity in reaching the certain name block, then: a) informing the second computing entity that the first computing entity takes over a performing of the corresponding case-insensitive FSE operation; and b) performing the corresponding case-insensitive FSE operation by the first computing entity.

Handling case sensitivity of filenames

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.

File systems capacity estimation

A method for reading a shared clock that is stored in a shared storage space of a storage system, the method may include (a) reading by a compute node a cached value of the shared clock when a time gap before a next update of the shared clock exceeds a time threshold, wherein the cached value is cached in the compute node and is valid during an allowable caching period, wherein the shared clock is shared by a group of compute nodes, wherein a default update of the shared clock has a cycle that exceeds the time threshold; and (b) reading by the compute node a read value of the shared clock when the time gap before the next update of the shared clock does not exceed the time threshold, wherein the read value of the shared clock is stored in the shared storage space.

Caching a shared clock of a distributed storage system

A method for managing access to a shared file system entity (FSE), the method includes (i) managing access requests for reading and writing accessed parts of the FSE, by a current point of access storage system (POASS), the current POASS currently acts as a point of access (POA) for the access requests; wherein stored parts of the FSE are stored at multiple POASSs, the multiple POASSs comprise the current POASS and former POASSs; (ii) determining, by the current POASS and while managing the access requests, to store the stored parts of the FSE at a fewer number of the former POASSs; and (iii) reducing, by two or more of the former POASSs, the number of former POASSs that store the stored parts of the FSE.

Global access to filesystem content

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.

Distributed task progress report

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.

Contention-reduced update of storage system parameters

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.

Stored entity metadata re-balancing upon storage expansion

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.

Recovery point objective compliant star replication

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.

Snapshot restore

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. Instructing the multiple compute entities, by the expansion manager, and during another phase of the lock metadata re-balancing that follows a release of all current LMUs, to acquire locks and check status of locks using the next translation function without using the current translation function.

Lock metadata re-balancing upon storage expansion

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.

Growing community of inventors

Tel Aviv, Israel

Avi Goren