Dell Products Inc.

Emc IP Holding Company LLC

David Ben-David

Vamsi K Vankamamidi

Kfir Wolfson

Oran Asher Baruch

Maor Rahamim

Jonathan Volij

Alexander Shknevsky

Techniques for rebuilding data in a data storage system are provided. A method includes: (a) identifying (i) a first set of degraded Ubers that contain no portions reserved for direct writing and (ii) a second set of degraded Ubers that contain at least one portion reserved for direct writing. Direct writing is a process that writes blocks to long-term storage prior to mapping those blocks in a metadata mapping structure. An Uber is a set of adjacent stripes across a respective Redundant Array of Independent Disks (RAID) array of the data storage system, and a degraded Uber is an Uber that includes at least one failed drive within its RAID array. The method further includes (b) initiating a rebuild of the first set of degraded Ubers; and (c) delaying a rebuild of each degraded Uber of the second set until all pending direct writes to blocks of that degraded Uber have been mapped by the metadata mapping structure.

Techniques for performing live rebuild in storage systems that operate a direct write mode

Disclosed is a method, apparatus, and system for processing a data update message in a multi-agent system comprising a plurality of agents, the operations comprising: receiving, at a second agent, the data update message comprising data for a node in a shared data tree and a first node context map from a first agent, the first node context map comprising last known contexts of all the agents for the node according to knowledge of the first agent; determining, at the second agent, whether any of three conditions relating to the first node context map and a second node context map is true, the second node context map comprising last known contexts of all the agents for the node according to knowledge of the second agent; and in response to determining that none of the three conditions relating to the first node context map and the second node context map is true, updating, at the second agent, the node based on the data update message from the first agent.

Non-centralized data synchronization for IoT and other distributed applications

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Beer Sheva, Israel

David Ben-David