When considering an Azure SQL instance, one of the decisions you need to make is the pricing level (Basic, Standard or Premium) and then for the selected level the number of DTU’s you need. Now you might be asking, "which service tier and performance level should I use and how many database throughput units (DTUs) am I using now?"
First lets look at explaining what a DTU is and then we can look at how the DTU Calculator will help.
“A DTU is a unit of measure of the resources that are guaranteed to be available to a standalone Azure SQL database at a specific performance level within a standalone database service tier. A DTU is a blended measure of CPU, memory, and data I/O and transaction log I/O in a ratio determined by an OLTP benchmark workload designed to be typical of real-world OLTP workloads. Doubling the DTUs by increasing the performance level of a database equates to doubling the set of resource available to that database.”
If you are looking to migrate an existing on-premises or SQL Server virtual machine workload to Azure SQL Database, you can use the DTU Calculator to approximate the number of DTUs needed.
Following the instructions for the DTU Calculator, download either the Command Line Utility or PowerShell Script and run it to measure your server resource utilization. You want to get an hour worth of data.
Once the script completes, go to the DTU Calculator website and enter in the number of cores for your server and then upload the CSV file that was generated. Then click on the “calculate” button as show below.
After the DTU Calculator measures your server resource utilization, it will provide you the best recommendation for the number of DTU’s you should be using in Azure SQL.