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.

Important

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.

pricing model

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.

Important

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.

Basic Standard Premium
Target workload Development and production Development and production Development and production
Uptime SLA 99.99% 99.99% 99.99%
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
In-memory OLTP N/A N/A 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?

Single databases

Basic Standard Premium
Maximum storage size* 2 GB 1 TB 4 TB
Maximum DTUs 5 3000 4000

For details on specific performance levels and storage size choices available for single databases, see SQL Database DTU-based resource limits for single databases.

Elastic pools

Basic Standard Premium
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

Important

  • 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.

Next steps