Compute and Storage options in Azure Database for PostgreSQL - Flexible Server

APPLIES TO: Azure Database for PostgreSQL - Flexible Server

You can create an Azure Database for PostgreSQL server in one of three different pricing tiers: Burstable, General Purpose, and Memory Optimized. The pricing tiers are differentiated by the amount of compute in vCores that can be provisioned, memory per vCore, and the storage technology used to store the data. All resources are provisioned at the PostgreSQL server level. A server can have one or many databases.

Resource / Tier Burstable General Purpose Memory Optimized
VM series B-series Ddsv4-series,
Dsv3-series
Edsv4-series,
Esv3 series
vCores 1, 2 2, 4, 8, 16, 32, 48, 64 2, 4, 8, 16, 20(v4), 32, 48, 64
Memory per vCore Variable 4 GB 6.75 to 8 GB
Storage size 32 GB to 16 TB 32 GB to 16 TB 32 GB to 16 TB
Database backup retention period 7 to 35 days 7 to 35 days 7 to 35 days

To choose a pricing tier, use the following table as a starting point.

Pricing tier Target workloads
Burstable Best for workloads that don’t need the full CPU continuously.
General Purpose Most business workloads that require balanced compute and memory with scalable I/O throughput. Examples include servers for hosting web and mobile apps and other enterprise applications.
Memory Optimized High-performance database workloads that require in-memory performance for faster transaction processing and higher concurrency. Examples include servers for processing real-time data and high-performance transactional or analytical apps.

After you create a server, the compute tier, number of vCores can be changed up or down and storage size can be changed up within seconds. You also can independently adjust the backup retention period up or down. For more information, see the Scale resources section.

Compute tiers, vCores, and server types

Compute resources can be selected based on the tier, vCores and memory size. vCores represent the logical CPU of the underlying hardware.

The detailed specifications of the available server types are as follows:

SKU Name vCores Memory Size Max Supported IOPS Max Supported I/O bandwidth
Burstable
B1ms 1 2 GiB 640 15 MiB/sec
B2s 2 4 GiB 1280 15 MiB/sec
General Purpose
D2s_v3 / D2ds_v4 2 8 GiB 3200 48 MiB/sec
D4s_v3 / D4ds_v4 4 16 GiB 6400 96 MiB/sec
D8s_v3 / D8ds_V4 8 32 GiB 12800 192 MiB/sec
D16s_v3 / D16ds_v4 16 64 GiB 18000 384 MiB/sec
D32s_v3 / D32ds_v4 32 128 GiB 18000 750 MiB/sec
D48s_v3 / D48ds_v4 48 192 GiB 18000 750 MiB/sec
D64s_v3 / D64ds_v4 64 256 GiB 18000 750 MiB/sec
Memory Optimized
E2s_v3 / E2ds_v4 2 16 GiB 3200 48 MiB/sec
E4s_v3 / E4ds_v4 4 32 GiB 6400 96 MiB/sec
E8s_v3 / E8ds_v4 8 64 GiB 12800 192 MiB/sec
E16s_v3 / E16ds_v4 16 128 GiB 18000 384 MiB/sec
E20ds_v4 20 160 GiB 18000 480 MiB/sec
E32s_v3 / E32ds_v4 32 256 GiB 18000 750 MiB/sec
E48s_v3 / E48ds_v4 48 384 GiB 18000 750 MiB/sec
E64s_v3 / E64ds_v4 64 432 GiB 18000 750 MiB/sec

Storage

The storage you provision is the amount of storage capacity available to your Azure Database for PostgreSQL server. The storage is used for the database files, temporary files, transaction logs, and the PostgreSQL server logs. The total amount of storage you provision also defines the I/O capacity available to your server.

Storage is available in the following fixed sizes:

Disk size IOPS
32 GiB Provisioned 120, Up to 3,500
64 GiB Provisioned 240, Up to 3,500
128 GiB Provisioned 500, Up to 3,500
256 GiB Provisioned 1100, Up to 3,500
512 GiB Provisioned 2300, Up to 3,500
1 TiB 5,000
2 TiB 7,500
4 TiB 7,500
8 TiB 16,000
16 TiB 18,000

Note that IOPS are also constrained by your VM type. Even though you can select any storage size independent of the server type, you may not be able to use all IOPS that the storage provides, especially when you choose a server with a small number of vCores.

You can add additional storage capacity during and after the creation of the server.

Note

Storage can only be scaled up, not down.

You can monitor your I/O consumption in the Azure portal or by using Azure CLI commands. The relevant metrics to monitor are storage limit, storage percentage, storage used, and IO percent.

Maximum IOPS for your configuration

SKU Name Storage Size in GiB 32 64 128 256 512 1,024 2,048 4,096 8,192 16,384
Maximum IOPS 120 240 500 1100 2300 5000 7500 7500 16000 18000
Burstable
B1ms 640 IOPS 120 240 500 640* 640* 640* 640* 640* 640* 640*
B2s 1280 IOPS 120 240 500 1100 1280* 1280* 1280* 1280* 1280* 1280*
General Purpose
D2s_v3 / D2ds_v4 3200 IOPS 120 240 500 1100 2300 3200* 3200* 3200* 3200* 3200*
D4s_v3 / D4ds_v4 6,400 IOPS 120 240 500 1100 2300 5000 6400* 6400* 6400* 6400*
D8s_v3 / D8ds_v4 12,800 IOPS 120 240 500 1100 2300 5000 7500 7500 12800* 12800*
D16s_v3 / D16ds_v4 18,000 IOPS 120 240 500 1100 2300 5000 7500 7500 16000 18000
D32s_v3 / D32ds_v4 18,000 IOPS 120 240 500 1100 2300 5000 7500 7500 16000 18000
D48s_v3 / D48ds_v4 18,000 IOPS 120 240 500 1100 2300 5000 7500 7500 16000 18000
D64s_v3 / D64ds_v4 18,000 IOPS 120 240 500 1100 2300 5000 7500 7500 16000 18000
Memory Optimized
E2s_v3 / E2ds_v4 3200 IOPS 120 240 500 1100 2300 3200* 3200* 3200* 3200* 3200*
E4s_v3 / E4ds_v4 6,400 IOPS 120 240 500 1100 2300 5000 6400* 6400* 6400* 6400*
E8s_v3 / E8ds_v4 12,800 IOPS 120 240 500 1100 2300 5000 7500 7500 12800* 12800*
E16s_v3 / E16ds_v4 18,000 IOPS 120 240 500 1100 2300 5000 7500 7500 16000 18000
E20ds_v4 18,000 IOPS 120 240 500 1100 2300 5000 7500 7500 16000 18000
E32s_v3 / E32ds_v4 18,000 IOPS 120 240 500 1100 2300 5000 7500 7500 16000 18000
E48s_v3 / E48ds_v4 18,000 IOPS 120 240 500 1100 2300 5000 7500 7500 16000 18000
E64s_v3 / E64ds_v4 18,000 IOPS 120 240 500 1100 2300 5000 7500 7500 16000 18000

When marked with a *, IOPS are limited by the VM type you selected. Otherwise IOPS are limited by the selected storage size.

Note

You may see higher IOPS in the metrics due to disk level bursting. Please see the documentation for more details.

Maximum I/O bandwidth (MiB/sec) for your configuration

SKU Name Storage Size, GiB 32 64 128 256 512 1,024 2,048 4,096 8,192 16,384
Storage Bandwidth, MiB/sec 25 50 100 125 150 200 250 250 500 750
Burstable
B1ms 10 MiB/sec 10* 10* 10* 10* 10* 10* 10* 10* 10* 10*
B2s 15 MiB/sec 15* 15* 15* 15* 15* 15* 15* 15* 15* 15*
General Purpose
D2s_v3 / D2ds_v4 48 MiB/sec 25 48* 48* 48* 48* 48* 48* 48* 48* 48*
D4s_v3 / D4ds_v4 96 MiB/sec 25 50 96* 96* 96* 96* 96* 96* 96* 96*
D8s_v3 / D8ds_v4 192 MiB/sec 25 50 100 125 150 192* 192* 192* 192* 192*
D16s_v3 / D16ds_v4 384 MiB/sec 25 50 100 125 150 200 250 250 384* 384*
D32s_v3 / D32ds_v4 750 MiB/sec 25 50 100 125 150 200 250 250 500 750
D48s_v3 / D48ds_v4 750 MiB/sec 25 50 100 125 150 200 250 250 500 750
D64s_v3 / Dd64ds_v4 750 MiB/sec 25 50 100 125 150 200 250 250 500 750
Memory Optimized
E2s_v3 / E2ds_v4 48 MiB/sec 25 48* 48* 48* 48* 48* 48* 48* 48* 48*
E4s_v3 / E4ds_v4 96 MiB/sec 25 50 96* 96* 96* 96* 96* 96* 96* 96*
E8s_v3 / E8ds_v4 192 MiB/sec 25 50 100 125 150 192* 192* 192* 192* 192*
E16s_v3 / E16ds_v4 384 MiB/sec 25 50 100 125 150 200 250 250 384* 384*
E20ds_v4 480 MiB/sec 25 50 100 125 150 200 250 250 480* 480*
E32s_v3 / E32ds_v4 750 MiB/sec 25 50 100 125 150 200 250 250 500 750
E48s_v3 / E48ds_v4 750 MiB/sec 25 50 100 125 150 200 250 250 500 750
E64s_v3 / E64ds_v4 750 MiB/sec 25 50 100 125 150 200 250 250 500 750

When marked with a *, I/O bandwidth is limited by the VM type you selected. Otherwise I/O bandwidth is limited by the selected storage size.

Reaching the storage limit

When you reach the storage limit, the server will start returning errors and prevent any further modifications. This may also cause problems with other operational activities, such as backups and WAL archival.

To avoid this situation, when the storage usage reaches 95% or if the available capacity is less than 5 GiB, the server is automatically switched to read-only mode.

We recommend to actively monitor the disk space that is in use, and increase the disk size ahead of any out of storage situation. You can set up an alert to notify you when your server storage is approaching out of disk so you can avoid any issues with running out of disk. For more information, see the documentation on how to set up an alert.

Storage auto-grow

Storage auto-grow is not yet available for Flexible Server.

Backup

The service automatically takes backups of your server. You can select a retention period from a range of 7 to 35 days. Learn more about backups in the concepts article.

Scale resources

After you create your server, you can independently change the vCores, the compute tier, the amount of storage, and the backup retention period. The number of vCores can be scaled up or down. The backup retention period can be scaled up or down from 7 to 35 days. The storage size can only be increased. Scaling of the resources can be done either through the portal or Azure CLI.

Note

The storage size can only be increased. You cannot go back to a smaller storage size after the increase.

When you change the number of vCores or the compute tier, the server is restarted for the new server type to take effect. During the moment when the system switches over to the new server, no new connections can be established, and all uncommitted transactions are rolled back. The time it takes to restart your server depends on crash recovery process and database activity at the time of restart. Restart typically takes one minute or less, however can be higher and can take several minutes depending upon transactional activity at time of restart. Scaling the storage works the same way, and requires restart.

To improve the restart time, we recommend to perform scale operations during non-peak hours, that will reduce the time needed to restart the database server.

Changing the backup retention period is an online operation.

Pricing

For the most up-to-date pricing information, see the service pricing page. To see the cost for the configuration you want, the Azure portal shows the monthly cost on the Pricing tier tab based on the options you select. If you don't have an Azure subscription, you can use the Azure pricing calculator to get an estimated price. On the Azure pricing calculator website, select Add items, expand the Databases category, and choose Azure Database for PostgreSQL to customize the options.

Next steps