Estimate RU/s using the Azure Cosmos DB capacity planner - SQL API



If you are planning a data migration to Azure Cosmos DB and all that you know is the number of vcores and servers in your existing sharded and replicated database cluster, please also read about estimating request units using vCores or vCPUs

Configuring your Azure Cosmos databases and containers with the right amount of provisioned throughput, or Request Units (RU/s), for your workload is essential to optimizing cost and performance. This article describes how to use the Azure Cosmos DB capacity planner to get an estimate of the required RU/s and cost of your workload when using the SQL API. If you are using API for MongoDB, see how to use capacity calculator with MongoDB article.

Capacity planner modes

Mode Description
Basic Provides a quick, high-level RU/s and cost estimate. This mode assumes the default Azure Cosmos DB settings for indexing policy, consistency, and other parameters.

Use basic mode for a quick, high-level estimate when you are evaluating a potential workload to run on Azure Cosmos DB. To learn more, see how to estimate cost with basic mode.

Estimate provisioned throughput and cost using basic mode

To get a quick estimate for your workload using the basic mode, navigate to the capacity planner. Enter in the following parameters based on your workload:

Input Description
API Choose SQL (Core) API
Number of regions Azure Cosmos DB is available in all Azure China regions. Select the number of regions required for your workload. You can associate any number of regions with your Cosmos account. See multiple-region distribution in Azure Cosmos DB for more details.
Multi-region writes If you enable multi-region writes, your application can read and write to any Azure region. If you disable multi-region writes, your application can write data to a single region.

Enable multi-region writes if you expect to have an active-active workload that requires low latency writes in different regions. For example, an IOT workload that writes data to the database at high volumes in different regions.

Multi-region writes guarantees 99.999% read and write availability. Multi-region writes require more throughput when compared to the single write regions. To learn more, see how RUs are different for single and multiple-write regions article.
Total data stored in transactional store Total estimated data stored(GB) in the transactional store in a single region.
Use analytical store Choose On if you want to use analytical store. Enter the Total data stored in analytical store, it represents the estimated data stored (GB) in the analytical store in a single region.
Item size The estimated size of the data item (for example, document), ranging from 1 KB to 2 MB.
Queries/sec Number of queries expected per second per region. The average RU charge to run a query is estimated at 10 RUs.
Point reads/sec Number of point read operations expected per second per region. Point reads are the key/value lookup on a single item ID and a partition key. To learn more about point reads, see the options to read data article.
Creates/sec Number of create operations expected per second per region.
Updates/sec Number of update operations expected per second per region. When you choose automatic indexing, the estimated RU/s for the update operation is calculated as one property being changed per an update.
Deletes/sec Number of delete operations expected per second per region.

After filling the required details, select Calculate. The Cost Estimate tab shows the total cost for storage and provisioned throughput. You can expand the Show Details link in this tab to get the breakdown of the throughput required for different CRUD and query requests. Each time you change the value of any field, select Calculate to recalculate the estimated cost.

Capacity planner basic mode

Next steps