What is database sharding?

Database sharding is the process of storing a large database across multiple machines. A single machine, or database server, can store and process only a limited amount of data. Database sharding overcomes this limitation by splitting data into smaller chunks, called shards, and storing them across several database servers.

Should you Shard a database?

The first part of any sharding strategy is to decide whether to shard at all. To generalize, sharding makes the most sense for a high-volume database that stores a large amount of data in a few simple tables. Sharding is especially compelling if a company expects a large increase in the size of its database.

How is a database organized before sharding?

Before the database is sharded, the example store table is organized in the following way: After sharding, one shard has half the rows from the table. The second shard contains the remainder of the rows. Sharding does not necessarily make any backup copies of the data. Each record is still only stored on a single server.