Database Replication & Sharding

Scale reads with replicas, scale writes with shards, and reason about the failure modes of both

Learn how single-leader, multi-leader and leaderless replication work, how quorums and failover behave, and how to shard a database by range, hash or directory — with shard-key selection, rebalancing, cross-shard queries and a worked 500M-user example.

Practice questions (6)

• Quorum Reads and Writes

  Intermediate · Free
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• Replication Lag Anomalies in a Social App

  Intermediate
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• Failover, Lost Writes and Split-Brain

  Advanced
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• Choosing a Shard Key for a Messaging Table

  Intermediate
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• Resharding From 8 to 12 Nodes Online

  Advanced
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Quizzes (1)