DTU-based purchasing model for Azure SQL Database
Azure SQL Database offers two purchasing models for compute, storage, and IO resources: a DTU-based purchasing model and a vCore-based purchasing model (preview). The following table and chart compare and contrast these two purchasing models.
For vCore-based purchasing model (preview), see vCore-based purchasing model
|Purchasing model||Description||Best for|
|DTU-based model||This model is based on a bundled measure of compute, storage, and IO resources. Performance levels are expressed in terms of Database Transaction Units (DTUs) for single databases and elastic Database Transaction Units (eDTUs) for elastic pools. For more on DTUs and eDTUs, see What are DTUs and eDTUs?||Best for customers who want simple, pre-configured resource options.|
|vCore-based model||This model allows you to independently scale compute and storage resources. It also allows you to use Azure Hybrid Benefit for SQL Server to gain cost savings.||Best for customers who value flexibility, control, and transparency.|
DTU-based purchasing model
The Database Throughput Unit (DTU) represents a blended measure of CPU, memory, reads, and writes. The DTU-based purchasing model offers a set of preconfigured bundles of compute resources and included storage to drive different levels of application performance. Customers who prefer the simplicity of a preconfigured bundle and fixed payments each month, may find the DTU-based model more suitable for their needs. In the DTU-based purchasing model, customers can choose between Basic, Standard, and Premium service tiers for both single databases and elastic pools. Service tiers are differentiated by a range of performance levels with a fixed amount of included storage, fixed retention period for backups, and fixed price. All service tiers provide flexibility of changing performance levels without downtime. Single databases and elastic pools are billed hourly based on service tier and performance level.
SQL Database Managed Instance, currently in public preview does not support a DTU-based purchasing model. For more information, see Azure SQL Database Managed Instance.
Choosing a service tier in the DTU-based purchasing model
Choosing a service tier depends primarily on business continuity, storage, and performance requirements.
|Target workload||Development and production||Development and production||Development and production|
|Backup retention||7 days||35 days||35 days|
|CPU||Low||Low, Medium, High||Medium, High|
|IO throughput (approximate)||2.5 IOPS per DTU||2.5 IOPS per DTU||48 IOPS per DTU|
|IO latency (approximate)||5 ms (read), 10 ms (write)||5 ms (read), 10 ms (write)||2 ms (read/write)|
|Columnstore indexing||N/A||S3 and above||Supported|
Performance level and storage size limits in the DTU-based purchasing model
Performance levels are expressed in terms of Database Transaction Units (DTUs) for single databases and elastic Database Transaction Units (eDTUs) for elastic pools. For more on DTUs and eDTUs, see What are DTUs and eDTUs?
|Maximum storage size*||2 GB||1 TB||4 TB|
For details on specific performance levels and storage size choices available for single databases, see SQL Database DTU-based resource limits for single databases.
|Maximum storage size per database*||2 GB||1 TB||1 TB|
|Maximum storage size per pool*||156 GB||4 TB||4 TB|
|Maximum eDTUs per database||5||3000||4000|
|Maximum eDTUs per pool||1600||3000||4000|
|Maximum number of databases per pool||500||500||100|
- Storage sizes greater than the amount of included storage are in preview and extra costs apply. For details, see SQL Database pricing.
- More than 1 TB of storage in the Premium tier is available in all regions except the following: UK North, West Central US, UK South2, China East, USDoDCentral, Germany Central, USDoDEast, US Gov Southwest, US Gov South Central, Germany Northeast, China North, US Gov East. More widespread availability is planned. In other regions, the storage max in the Premium tier is limited to 1 TB. See P11-P15 Current Limitations.
For details on specific performance levels and storage size choices available for elastic pools, see SQL Database DTU-based resource limits.
- For details on specific performance levels and storage size choices available, see SQL Database DTU-based resource limits and SQL Database vCore-based resource limits.
- See SQL Database FAQ for answers to frequently asked questions.
- Learn about Azure Subscription and Service Limits, Quotas, and Constraints