Microsoft Azure


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

Depending on your instance size, Atlas supports the following Azure regions:

Azure Region Location M0 Free Tier Support M2/M5 Shared Tier Support
centralus Iowa (Central US)    
eastus Virginia (East US)    
eastus2 Virginia (East US) check square icon check square icon
northcentralus Illinois (North Central US)    
westus California (West US)    
southcentralus Texas (South Central US)    
northeurope Ireland (North Europe)   check square icon
westeurope Netherlands (West Europe) check square icon  
francecentral Paris (France)    
westus2 California (West US 2)    
canadaeast Quebec City (Canada East)    
canadacentral Toronto (Canada Central)    
brazilsouth Sao Paulo (Brazil South)    
australiaeast New South Wales (Australia East)    
australiasoutheast Victoria (Australia Southeast)    
uksouth London (UK South)    
ukwest Cardiff (UK West)    
centralindia Pune (Central India)    
westindia Mumbai (West India)    
southindia Chennai (South India)    
eastasia Hong Kong (East Asia) check square icon  
japaneast Tokyo (Japan East)    
japanwest Osaka (Japan West)    
southeastasia Singapore (Southeast Asia)    
koreacentral Seoul (Korea Central)    
koreasouth Busan (Korea South)    

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]

The following instance sizes are available:

Instance size Maximum disk storage
M0 512MB
M2 2GB
M5 5GB
M20 128GB
M30 256GB
M40 512GB
M50 2TB
M60 4TB
M90 4TB

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.

Regions with Only Two Fault Domains

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