Can you explain the concept of horizontal database scaling?

Horizontal database scaling is an approach where the load is distributed across multiple servers (nodes), each storing a part of the data. Unlike vertical scaling (increasing resources of a single server), horizontal scaling allows adding new servers to handle a larger volume of requests and data.

Example: if you have a user table, you can split it into several parts (shards) based on ID range or geographic location, and store each shard on a separate server. This increases system performance and fault tolerance.

Main advantages:

• Scalability: easy to add new nodes.
• Fault tolerance: if one node fails, others continue to operate.
• Load distribution: requests are processed in parallel.

However, horizontal scaling requires a well-thought-out architecture, such as sharding mechanisms and data consistency.