Microsoft Azure

Atlas supports deploying clusters onto Microsoft Azure. This page provides reference material related to Atlas cluster deployments on Azure .

Depending on your cluster tier, Atlas supports the following Azure regions. The Atlas Region is the corresponding region name used by Atlas processes.

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Regions with Availability Zones guarantee higher uptime for dedicated clusters deployed after September 12, 2019. Existing clusters in regions with Availability Zones are not automatically migrated. To learn more about Availability Zones, see Azure 's documentation.

Azure RegionLocationAtlas RegionM0 Free Tier SupportM2/M5 Shared-Tier SupportAvailability Zones
centralusIowa, USAUS_CENTRAL
eastusVirginia (East US)US_EAST
eastus2Virginia, USAUS_EAST_2
northcentralusIllinois, USAUS_NORTH_CENTRAL
westusCalifornia, USAUS_WEST
southcentralusTexas, USAUS_SOUTH_CENTRAL
westus2Washington, USAUS_WEST_2
westcentralusWyoming, USAWEST_CENTRAL_US
brazilsouthSao Paulo, BrazilBRAZIL_SOUTH
canadaeastQuebec City, QC, CanadaCANADA_EAST
canadacentralToronto, ON, CanadaCANADA_CENTRAL
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Due to their higher cost, it is recommended to use Switzerland West or UAE Central as a secondary disaster recovery (DR) region in a multi-region cluster if necessary.

  • Use Switzerland West in conjunction with Switzerland North.
  • Use UAE Central in conjunction with UAE North.

Each Atlas cluster tier comes with a default set of resources. Atlas provides the following resource configuration options:

Custom Storage Size
The size of the server root volume. Atlas clusters deployed onto Azure use premium storage disks. [1]
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RAM Availability
The actual amount of RAM available to each cluster tier might be slightly less than the stated amount, due to memory that the kernel reserves.
The following clusters tiers are available:
Cluster TiersDefault StorageDefault RAM
M22 GBShared
M55 GBShared
M1032 GB2 GB
M2032 GB4 GB
M3032 GB8 GB
M40128 GB16 GB
M40 Low-CPU (R40)128 GB16 GB
M50128 GB32 GB
M50 Low-CPU (R50)128 GB32 GB
M60128 GB64 GB
M60 Low-CPU (R60)128 GB64 GB
M80256 GB128 GB
M80 Low-CPU (R80)256 GB128 GB
M200256 GB256 GB
M200 Low-CPU (R200)256 GB256 GB
M300 Low-CPU (R300) 1512 GB384 GB
M400 Low-CPU (R400)512 GB432 GB
1 Not available in the following regions:
  • germanywestcentral
  • switzerlandnorth
  • switzerlandwest
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Cluster Tier & API Naming Conventions
For purposes of management with the Atlas API, cluster tier names that are prepended with R instead of an M (R40 for example) run a low-CPU version of the cluster. When creating or modifying a cluster with the API, be sure to specify your desired cluster class by name with the providerSettings.instanceSizeName attribute.
Important With Circle IconCreated with Sketch.Important
Multi-Cloud Low-CPU clusters
Low-CPU cluster tiers (R40, R50, R60, etc) are available in multi-cloud cluster configurations as long as the cluster tier is available for all the regions that the cluster uses.
Workloads typically require less than 2TB.

Atlas configures the following resources automatically and does not allow user modification:

Storage Speed
The input/output operations per second (IOPS) [1] the system can perform. This value is fixed based on the specified custom storage size.
Encrypted Storage Volumes
Azure storage volumes are always encrypted.

Each Azure region includes a set number of fault domains. Fault domains consist of a group of virtual machines that share a common power source and network switch. For regions that have at least three fault domains (3FD), Atlas deploys clusters across three fault domains. For regions that only have two fault domains (2FD), Atlas deploys clusters across two fault domains.

The Atlas Add New Cluster form marks regions that support 3FD clusters as Recommended, as they provide higher availability.

The number of fault domains in a region has no effect on the number of MongoDB nodes Atlas can deploy. MongoDB Atlas clusters are always made of replica sets with a minimum of three MongoDB nodes.

For general information on Azure regions and fault domains, see Manage the availability of Windows virtual machines in Azure

If the selected Azure region has at least three fault domains, Atlas clusters are split across three fault domains. For example, a three node replica set cluster would have one node deployed onto each zone.

A 3-node replica set deployed across a 3-fault-domain Azure region.

3FD clusters have higher availability compared to 2FD clusters. However, not all regions support 3FD clusters.

If the selected Azure region has two fault domains, Atlas clusters are split across the two fault domains. For example, a three node replica set cluster would have two nodes deployed to one zone and the remaining node deployed to the other zone.

A 3-node replica set deployed across a 2-fault-domain Azure region.

2FD clusters have a higher chance of loss of availability in the event of the loss of an zone than 3FD clusters. However, where latency or location are a priority, a region that supports 2FD clusters may be preferred.

[1](1, 2) For detailed documentation on Azure storage options, see High-performance Premium Storage and managed disks for VMs
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