In the Further reading section, you will find a capacity calculator—a tool that enables you to plan your Cosmos DB instance and estimate the required RUs. As mentoned previously, in this particular service you are not defining the number of instances or clusters. Instead, while creating a container, you have to state your expected throughput for that specific collection (or a set of collections). Thanks to an Service Level Agreement (SLA) for Azure Cosmos DB, that value will be guaranteed for you. Additionally, even if you replicate a database to another region, you can expect that problems in one region will not affect others.
There is one important definition of 1 request unit—it is the processing capacity, ...
