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.
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 Region||Location||Atlas Region||Availability Zones|
|Virginia (East US)|
|Sao Paulo, Brazil|
|Quebec City, QC, Canada|
|Toronto, ON, Canada|
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.
Cluster Configuration Options¶
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.
The following clusters tiers are available:NoteRAM AvailabilityThe actual amount of RAM available to each cluster tier might be slightly less than the stated amount, due to memory that the kernel reserves.
1 Not available in the following regions:
Cluster Tiers Default Storage Default RAM M2 2 GB Shared M5 5 GB Shared M10 32 GB 2 GB M20 32 GB 4 GB M30 32 GB 8 GB M40 128 GB 16 GB M40 Low-CPU (R40) 128 GB 16 GB M50 128 GB 32 GB M50 Low-CPU (R50) 128 GB 32 GB M60 128 GB 64 GB M60 Low-CPU (R60) 128 GB 64 GB M80 256 GB 128 GB M80 Low-CPU (R80) 256 GB 128 GB M200 256 GB 256 GB M200 Low-CPU (R200) 256 GB 256 GB M300 Low-CPU (R300) 1 512 GB 384 GB M400 Low-CPU (R400) 512 GB 432 GB
NoteCluster Tier & API Naming ConventionsFor purposes of management with the Atlas API, cluster tier names that are prepended with
Rinstead of an
R40for 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.instanceSizeNameattribute.Workloads typically require less thanImportantMulti-Cloud Low-CPU clustersLow-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.
Atlas configures the following resources automatically and does not allow user modification:
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 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
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.
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.
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, 2) For detailed documentation on Azure storage options, see High-performance Premium Storage and managed disks for VMs|