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In the world of cloud databases, Azure SQL Database presents two pricing models: Database Transaction Unit (DTU) and vCore. Both models offer a variety of service tiers to accommodate different requirements and budgets. But which one is best for your business needs? In this blog post, we delve into the differences between the DTU and vCore models and provide some guidelines to help you make an informed decision.

The DTU-based purchasing model offers bundled compute, storage, and IO resources. This model is best for customers who want a simple, pre-configured bundle of resources. A key benefit of the DTU model is its simplicity: you select a performance level, and all the resources you need are included.

-- SQL Server 2016/2017 example to check DTU usage
SELECT * 
FROM sys.dm_db_resource_stats 
ORDER BY end_time DESC;

On the other hand, the vCore-based purchasing model offers flexibility to independently scale compute and storage resources. This model is best for customers who require more control over their database resources and want to scale compute and storage separately. It is also good for those who want to take advantage of Azure Hybrid Benefit for SQL Server.

-- MySQL 5.7 example to check CPU usage, which impacts vCore
SHOW GLOBAL STATUS LIKE 'Uptime';
SHOW GLOBAL STATUS LIKE 'Questions';

When comparing DTU and vCore, it's important to consider your application's requirements. For example, if you need more control over your resources and want to scale compute and storage separately, vCore may be the better choice. However, if you prefer a simple, pre-configured bundle of resources, DTU may be more suitable.

-- DB2 11.1 example to check CPU and IO usage
SELECT SUBSTR(workload_name,1,15) AS wl_name, 
       total_cpu_time, 
       total_io_time 
FROM TABLE(MON_GET_WORKLOAD(NULL, -2)) 
WHERE total_cpu_time > 0 
ORDER BY total_cpu_time DESC;

In conclusion, the choice between Azure SQL Database's DTU and vCore models depends on your specific needs and budget. The DTU model simplifies the purchasing experience by providing a pre-configured bundle of resources, while the vCore model provides greater flexibility and control over resources. By understanding these models, you can make the best decision for your business.