Microsoft Azure


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

Atlas supports the following Azure regions:

Azure Region Location
eastus Virginia (East US)
eastus2 Virginia (East US)
centralus Iowa (Central US)
northcentralus Illinois (North Central US)
southcentralus Texas (South Central US)
westus California (West US)
northeurope Ireland (North Europe)
westeurope Netherlands (West Europe)

Instance Configuration Options

Each Atlas instance size 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] Atlas supports the following storage sizes:

  • 128GB
  • 512GB
  • 1024GB (1TB)

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.

Azure Fault Domains

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 affect 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

Regions with at Least Three Fault Domains

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.

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