Azure Cosmos DB Partitions Across Regions

Cosmos DB data is organized into several layers of hierarchy. Shown here is an example deployment with a single database and a container replicated across two Azure regions.

A customer creates a Cosmos DB account within an Azure subscription. Databases are created within the account, and containers are created within each database.

Containers are divided into logical and physical partitions to distribute storage and database activity across compute resources. Logical partitions are created by the service based on a partition key specified by the customer for a container. The partition key maps to a property on items stored in the database. The selected partition key shown here is Division. Each value of Division is stored in a separate logical partition; in this example, Division has six values, so there are six logical partitions. 

Physical partitions are created by the service based on the number and size of logical partitions. Each logical partition resides within a single physical partition, but a physical partition can contain multiple logical partitions.