Vast Data Ltd.

Ohad Ben-Yehuda

Avi Goren

Oren Ashkenazi

Uri Weissbrem

Oded Sonin

Nadav Halwany

Benny Lodman

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. For each external FSE, an external content is indicative of differences in the external FSEs between (a) a last external FSE snapshot that preceded the previous replication cycle PIT and was generate by an external FSE snapshot process, and (b) a last external FSE snapshot that preceded the current replication cycle PIT and was generate by the external FSE snapshot process. The external FSE snapshot process and a process for generating the current replication cycle are not mutually synchronized.

Cascaded replication

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 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 snapshot reversion, the method may include initializing a recovery of a storage system, from a failure that stopped a replication of a failed replication snapshot to an other storage system; wherein the other storage system reverted to an older snapshot not stored in the storage system; and reverting to the older snapshot, by the storage system using older snapshot metadata and data received from the storage system; wherein the older snapshot data may include a non-existing indication for a snapshot segment that existed in a snapshot that followed the older snapshot and not exists at the older snapshot, and wherein the data may include one or more older snapshot segments; wherein the reverting to the older snapshot is executed without undoing changes that were made since the older snapshot.

Growing community of inventors

Tel Aviv, Israel

Ohad Ben-Yehuda