Facebook, Inc.

Liyin Tang

Kannan Muthukkaruppan

Karthik Ranganathan

Arjen Roodselaar

Amitanand S Aiyer

Rishit Manit Shroff

A region-based placement policy that can be used to achieve a better distribution of data in a clustered storage system is disclosed herein. The clustered storage system includes a master module to implement the region-based placement policy for storing one or more copies of a received data across many data nodes of the clustered storage system. When implementing the region-based placement policy, the master module splits the received data into one or more regions, where each region includes a contiguous portion of the received data. Further, for each of the plurality of regions, the master module stores complete copies of the region in a subset of the data nodes.

Placement policy

The disclosure is directed to failover mechanisms in a distributed computing system. A region of data is managed by multiple region servers. One of the region servers is elected as a 'leader' and the remaining are 'followers.' The leader serves the read/write requests from a client. The leader writes the data received from the client into the in-memory store and a local write-ahead log (&#x201c;WAL&#x201d;), and synchronously replicates the WAL to the followers. A region server designated as an &#x201c;active&#x201d; region server synchronizes a distributed data store with the data from the WAL. Active witness followers apply the data from the WAL to their in-memory store while shadow witness followers do not. Different types of servers provide failover mechanisms with different characteristics. A leader is elected based on their associated ranks&#x2014;higher the rank, higher the likelihood of electing itself as a leader.

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Fremont, CA, United States of America

Liyin Tang