Horizontal scaling

Horizontal scaling, or sharding, refers to partitioning the data from one single big table in a database across multiple independent databases based on a sharding or partitioning key. For example, a customer table is partitioned across multiple independent databases on CustomerID. Each independent database stores data for one or more customers.

Note

Sharding is only available in SQL Database and it's not available for SQL Managed Instance.

Horizontal scaling can be helpful in the following situations:

• The data is too big to fit into one single database.
• The data is to be distributed to different locations for improved performance or for compliance. For example, European customers will get improved performance if their data is in a European datacenter rather than an Asian datacenter.
• Isolating tenants or customers to a database of their own for better management and performance. If all of the customer data is in a single database and...