Configure a Global Cluster

This section covers enabling Global Writes on an Atlas cluster.

  • Atlas supports enabling Global Writes when deploying an M30 or greater sharded cluster.
  • Once deployed, you cannot convert a Global Cluster to a standard sharded cluster. Thoroughly familiarize yourself with the Global Clusters Overview and Reference Documentation before creating a Global Cluster.
  • If this is the first dedicated paid cluster for the selected region or regions and you plan on creating one or more VPC peering connections, review VPC Peering Connections before continuing.
  1. In the Create New Cluster dialog, click Global Cluster Configuration to expand the section.
  2. Toggle Enable Global Writes (M30 and Up) to On to display the Global Cluster configuration.
Screenshot of the Atlas Global Writes Dialog

Each cloud provider has a selection of global regions to which Atlas can deploy a zone. The choice of cloud provider may support or constrict your ability to deploy a zone to specific geographic locations. The configuration options available and the cost for running the cluster may also vary depending on cloud provider selection.


Atlas provides three options for configuring your Global Cluster zones:

  • Configure Global Writes Zones Using a Template
  • Configure a Global Writes Single Region Zone
  • Configure a Global Writes Multi Region Zone

Select the appropriate tab based on how you would like to configure your Global Cluster zones.

Atlas provides two templates for configuring Global Writes zones for the cluster, each with a description of the purpose of its underlying configuration. Click on a template to view the Zone Map for that template. The Zone Map provides a visual description of the cluster zone configuration, including estimates of geographic latency and coverage.

Screenshot of the Atlas Global Templates

Click Zone configuration summary below the zone map to view a summary of each zone in the Global Cluster. Atlas provides the following validations for each zone:

Low latency reads and writes in <geography>
Indicates the geographic locale for which the zone supports low latency reads and writes. The exact geographic locale specified depends on the preferred Region for that zone. You can modify the zone's preferred region in the Zone Configuration section.
Local reads in all other zones

Indicates whether data in this zone is replicated to every other zone for local secondary reads by clients in those zones.

Click the Configure Local Reads in All Zones button in the Zone configuration summary to automatically configure every zone in the cluster for local reads.

(Not) Available during partial region outage

Indicates whether the zone supports high availability, such that a majority of electable nodes remain healthy and reachable in the event of a partial region outage. Regions marked as Recommended in the Atlas UI support high availability during partial regional outages.

See also:
(Not) Available during full region outage
Indicates whether the zone supports high availability, such that a majority of electable nodes remain healthy and rechable in the event of a complete regional outage.

By default each template deploys a series of single-region zones and builds a map of country and subdivision locations geographically near each zone. MongoDB uses this location-zone map to route read and write operations which contain location data to the shard or shards in the corresponding zone.

Click the Configure Location Mappings in the Zone Map to view the list of location-zone mappings. To customize the location-zone mapping, click the Zone dropdown for a given Location Name and select a new zone. Click the Reset button to reset a custom mapping for any given location. Click the Reset All Zone mappings button to reset all custom mappings for the cluster.

You can make additional configuration changes to each zone after selecting a zone template. For instructions, see the Single Region Zone tab.

You can also create Multi-region zones. For instructions, see the Multi-Region Zone tab. Clicking Configure Local Reads in All Zones converts all zones to multi-region.

Click View Zone Templates in the Zone Map to return to the template selection.


Once you have configured your global cluster options, you can move on to the Cluster Tier step of cluster creation.

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