What is the difference between replication and sharding?

Replication and sharding are database scaling strategies.

Replication:

• Creating identical copies of data on multiple servers.
• Used to increase availability and read performance.
• Writes usually occur on a primary server (master), while reads can be distributed among replicas (slaves).
• Provides data redundancy.

Sharding:

• Horizontal partitioning of data into smaller, independent parts (shards).
• Each part is stored on a separate server or cluster of servers.
• Used for scaling both reads and writes when data volume or load exceeds the capacity of a single server.
• Requires logic to determine which shard contains the needed data.