How do data sharding and replication differ in data distribution methods?

Sharding and replication are two different approaches to data distribution in databases and storage systems.

Sharding is the division of data into parts (shards), where each part is stored on a separate server or node. Each shard contains a unique set of data, and together they cover the entire database. This helps to scale the system horizontally by distributing load and data volume.

Replication is copying the same data to multiple servers. All replicas contain the same information, which increases fault tolerance and availability: if one server fails, data is accessible on another.

Key differences:

• Sharding divides data across different nodes, replication copies data to multiple nodes.
• Sharding improves scalability in volume, replication enhances reliability and availability.

Example:

• In sharding, user data can be distributed by regions: users from Europe on one shard, from Asia on another.
• In replication, all data is duplicated on several servers for backup.