Resource limits for single databases using the DTU purchasing model - Azure SQL Database

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Applies to: Azure SQL Database

This article provides the detailed resource limits for Azure SQL Database single databases using the DTU purchasing model.

Each read-only replica has its own resources such as DTUs, workers, and sessions. Each read-only replica is subject to the resource limits detailed later in this article.

Single database: Storage sizes and compute sizes

The following tables show the resources available for a single database at each service tier and compute size. You can set the service tier, compute size, and storage amount for a single database using:

Important

For scaling guidance and considerations, see Scale a single database

Basic service tier

Compute size Basic
Max DTUs 5
Included storage (GB) 2
Max storage (GB) 2
Max in-memory OLTP storage (GB) N/A
Max concurrent workers 30
Max concurrent logins 30
Max concurrent external connections 1 3
Max concurrent sessions 300

1 See External Connections for additional details on what counts as an external connection.

Important

The Basic service tier provides less than one vCore (CPU). For resource-intensive workloads, a service tier of S3 or greater is recommended.

Database restore operations can be resource-intensive and may require a service objective of S3 or greater. Once restored, a database can be scaled down to a lower service objective if required.

Regarding data storage, the Basic service tier is placed on Standard Page Blobs. Standard Page Blobs use hard disk drive (HDD)-based storage media and are best suited for development, testing, and other infrequently accessed workloads that are less sensitive to performance variability.

Standard service tier

Compute size S0 S1 S2 S3
Max DTUs 10 20 50 100
Included storage (GB) 1 250 250 250 250
Max storage (GB) 250 250 250 1024
Max in-memory OLTP storage (GB) N/A N/A N/A N/A
Max concurrent workers 60 90 120 200
Max concurrent logins 60 90 120 200
Max concurrent external connections 2 6 9 12 20
Max concurrent sessions 600 900 1200 2400

1 See SQL Database pricing options for details on additional cost incurred due to any extra storage provisioned.

2 See External Connections for additional details on what counts as an external connection.

Important

The Standard S0, S1 and S2 tiers provide less than one vCore (CPU). For resource-intensive workloads, a service tier of S3 or greater is recommended.

Restoration operations can be resource-intensive and often require a service tier of S3 or greater.

Regarding data storage, the Standard S0 and S1 service tiers are placed on Standard Page Blobs. Standard Page Blobs use hard disk drive (HDD)-based storage media and are best suited for development, testing, and other infrequently accessed workloads that are less sensitive to performance variability.

Standard service tier (continued)

Compute size S4 S6 S7 S9 S12
Max DTUs 200 400 800 1600 3000
Included storage (GB) 1 250 250 250 250 250
Max storage (GB) 1024 1024 1024 1024 1024
Max in-memory OLTP storage (GB) N/A N/A N/A N/A N/A
Max concurrent workers 400 800 1600 3200 6000
Max concurrent logins 400 800 1600 3200 6000
Max concurrent external connections 2 40 80 150 150 150
Max concurrent sessions 4800 9600 19200 30000 30000

1 See SQL Database pricing options for details on additional cost incurred due to any extra storage provisioned.

2 See External Connections for additional details on what counts as an external connection.

Premium service tier

Compute size P1 P2 P4 P6 P11 P15
Max DTUs 125 250 500 1000 1750 4000
Included storage (GB) 1 500 500 500 500 4096 2 4096 2
Max storage (GB) 1024 1024 1024 1024 4096 2 4096 2
Max in-memory OLTP storage (GB) 1 2 4 8 14 32
Max concurrent workers 200 400 800 1600 2800 6400
Max concurrent logins 200 400 800 1600 2800 6400
Max concurrent external connections 3 20 40 80 150 150 150
Max concurrent sessions 30000 30000 30000 30000 30000 30000

1 See SQL Database pricing options for details on additional cost incurred due to any extra storage provisioned.

2 From 1024 GB up to 4096 GB in increments of 256 GB.

3 See External Connections for additional details on what counts as an external connection.

Note

For additional information on storage limits in the Premium service tier, see Storage space governance.

Tempdb sizes

The following table lists tempdb sizes for single databases in Azure SQL Database:

Service-level objective Maximum tempdb data file size (GB) Number of tempdb data files Maximum tempdb data size (GB)
Basic 13.9 1 13.9
S0 13.9 1 13.9
S1 13.9 1 13.9
S2 13.9 1 13.9
S3 32 1 32
S4 32 2 64
S6 32 3 96
S7 32 6 192
S9 32 12 384
S12 32 12 384
P1 13.9 12 166.7
P2 13.9 12 166.7
P4 13.9 12 166.7
P6 13.9 12 166.7
P11 13.9 12 166.7
P15 13.9 12 166.7

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