Choosing a DTU-based service tier, performance level, and storage resources
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 DTU-based service tier
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|
Single database DTU and storage limits
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|
Elastic pool eDTU, storage, and pooled database limits
|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|
More than 1 TB of storage in the Premium tier is currently 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. 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 single databases, see SQL Database DTU-based resource limits for single databases.
- For details on specific performance levels and storage size choices available for elastic pools, see SQL Database DTU-based resource limits.