FAILOVER MECHANISM IN A DISTRIBUTED COMPUTING SYSTEM

摘要

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 (“WAL”), and synchronously replicates the WAL to the followers. A region server designated as an “active” 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—higher the rank, higher the likelihood of electing itself as a leader.

主权项

1. A method performed by a computing system, comprising:
receiving a data access request including a dataset from a client computing system at a distributed computing system, the distributed computing system including multiple computing servers hosting a region of data associated with the distributed computing system, the computing servers distributed across multiple clusters, wherein one of the computing servers is a leader server and a remaining of the computing servers are follower servers, and wherein some of the computing servers are active servers, active witness servers and shadow witness servers; writing, by the leader server, the dataset to a log file at a data storage system associated with the leader server; replicating, by the leader server, the log file to the follower servers; and updating, by an active server of the active servers, a distributed data storage system associated with a first cluster of the clusters to which the leader server belongs with the dataset from the log file.