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Modify a Cluster

Atlas Configuration Options

You can modify the following properties of your Atlas cluster:

Global Cluster Configuration

You can enable global writes for your cluster or modify existing global cluster configurations.

Important

You cannot disable Global Writes for a cluster once deployed.

Cloud Provider & Region

You can only modify the cloud provider backing your cluster when you upgrade from an Atlas M0 Free Tier or M2/M5 Shared Tier cluster to a larger cluster. Transitioning to a different provider changes your cluster connection string. Consider scheduling a maintenance window to update your applications with the new connection string to resume connectivity to the cluster. Atlas migrates data to the new cluster.

Note

You cannot modify the cloud provider of M10 or larger dedicated clusters. If you wish to use a different cloud provider for a dedicated cluster, create a new cluster and use the Atlas Live Migration service to migrate data from the original cluster to the new one:

For dedicated clusters with a Cluster Tier of M10 or larger, you can modify cluster’s region.

Deploy or Configure a multi-region cluster

You can deploy or modify a multi-region cluster.

Only available for cluster with a Cluster Tier of M10 or larger.

Cluster Tier You can modify the cluster tier.
Cluster Storage Options

You can modify the storage options for the selected cluster tier.

Only available for cluster with a Cluster Tier of M10 or larger.

Cluster Autoscaling Options

You can modify the cluster’s autoscaling options.

Only available for M10+ clusters using the General storage class.

MongoDB Version

You can upgrade the major MongoDB version of the cluster.

Only available for cluster with a Cluster Tier of M10 or larger.

You cannot downgrade the MongoDB version of a cluster.

Deploy a Sharded Cluster

If your cluster is a replica set, you can upgrade the deployment to a sharded cluster.

Only available for clusters with a Cluster Tier of M30 or larger.

Modify the Number of Shards

You can configure the number of shards in the sharded cluster.

Only available for sharded cluster deployments.

Enable or Disable Backup You can enable or disable backups for the cluster. Only available for clusters with a Cluster Tier of M10 or larger.
Enable or Disable the Business Intelligence Connector

You can enable or disable the BI Connector for Atlas for this cluster.

The MongoDB Connector for Business Intelligence for Atlas (BI Connector) is only available for M10 and larger clusters.

The BI Connector is a powerful tool which provides users SQL-based access to their MongoDB databases. As a result, the BI Connector performs operations which may be CPU and memory intensive. Given the limited hardware resources on M10 and M20 cluster tiers, you may experience performance degradation of the cluster when enabling the BI Connector. If this occurs, upgrade to an M30 or larger cluster or disable the BI Connector.

Confirm and Deploy Confirm and deploy your cluster with the selected changes.

Considerations

Migration, Availability, and Performance Impact

The time required for an initial sync and resynchronizing data across storage volumes increases linearly with the amount of data in the cluster. Making changes to a cluster often requires migrating to new servers and storage volumes, which can take a long time. However, cluster changes can be made more quickly in some cases. For example, changing the tier of a cluster on AWS does not require an initial sync.

Changes to Free/Shared Tier clusters result in limited downtime

All changes to M0, M2, and M5 clusters require 7-10 minutes of downtime.

To maximize availability:

  • For a replica set, Atlas migrates one node at a time, starting with the secondary nodes first and then the primary.
  • For a sharded cluster, Atlas performs the migration of the shards independently of each other. For each shard (i.e. replica set), Atlas migrates one node at a time, starting with the secondary nodes first and then the primary.

Retryable writes should prevent any write errors during the election of a new primary. On average, an election can take five seconds.

Migration can affect performance if your primary is already reaching operational capacity: each newly migrated replica set node must perform an initial sync from the primary, adding to the operational load. Migrations can also affect performance if read preferences are set to read from secondaries: the replica set is down one secondary during the migration.

If the workload on the Atlas cluster is such that it impedes operations, including the ability to scale, MongoDB Atlas may, in some situations, create indexes in your cluster as a safeguard.

Billing

As you modify your cluster, you can compare the costs of different options before applying them. The Cluster Overview box displays the cost of the selected configuration, excluding data transfer.

Free Tier

Upgrading an M0 Free Tier cluster to an M2 or greater paid tier cluster starts billing for the cluster. See Billing for complete documentation on Atlas billing.

The following sections provide complete documentation for each of the Atlas cluster scaling configuration options.

Open the Editing Cluster Dialog

For the cluster you want to modify, click the ellipses icon, then select Edit Configuration.

Alternatively, if you are already viewing the specific cluster, click the Configuration button.

For M0 Free Tier clusters, you can also click the Upgrade button for the cluster.

Modify the Global Cluster Configuration

Important

You cannot disable Global Writes for a cluster once deployed.

You can enable global writes for your cluster or modify existing global cluster configurations.

To learn more about global clusters, see Global Clusters.

To learn how to configure global clusters and map your global cluster zones, see Configure a Global Cluster.

Modify the Cloud Provider & Region

Considerations

  • You can only modify the cloud provider backing your cluster when you upgrade from an Atlas M0 Free Tier or M2/M5 Shared Tier cluster to a larger cluster. Transitioning to a different provider changes your cluster connection string. Consider scheduling a maintenance window to update your applications with the new connection string to resume connectivity to the cluster. Atlas migrates data to the new cluster.
  • You cannot modify the cloud provider of M10 or larger dedicated clusters. If you wish to use a different cloud provider for a dedicated cluster, create a new cluster and use the Atlas Live Migration service to migrate data from the original cluster to the new one:

Select Cloud Provider & Region to view the currently configured cloud provider and region for the cluster.

Select the desired cloud provider and region for your cluster.

If you are upgrading from an Atlas M0 Free Tier or M2/M5 shared-tier cluster, you can change the cloud provider backing your cluster by selecting from the available cloud providers.

For details on cloud providers and regions for both single-region and multi-region clusters, see Cloud Providers and Regions.

For more information on moving a cluster to a new region, see Move a Cluster.

Modify the Cluster Tier

You can change the cluster tier, as well as the memory, storage, and IOPS (speed) specifications for the selected cluster.

Free and Shared-Tier Cluster Considerations

  • You cannot downgrade an M10+ cluster to an M0 Free Tier or M2/M5 Shared-Tier Starter instance size.
  • Changing the cluster tier from an M0 Free Tier or M2/M5 Shared-Tier cluster to an M10 or larger cluster tier requires downtime.

Select your preferred cluster tier. The selected instance size dictates the memory, storage, and IOPS specification for each data-bearing server [1] in the cluster.

Note

Clusters which utilize NVMe storage must perform an initial sync when upgrading to a higher cluster tier.

For more information on cluster tiers, see Cluster Tier.

From the Cluster Tier section, you can also:

Modify Additional Settings

From the Additional Settings section, you can

Upgrade the MongoDB Version of the Cluster

Important

Before you upgrade your cluster, refer to the current recommended best practices for major version upgrades.

  1. Select Additional Settings to view the currently configured MongoDB version for the cluster.

    Atlas always upgrades the cluster to the latest stable release of the specified version via a rolling process to maintain cluster availability.

    You cannot downgrade the cluster to an earlier MongoDB version.

  2. From the Select a version dropdown, select the new MongoDB version.

    Atlas supports the following upgrade paths:

    • MongoDB 3.4 -> MongoDB 3.6
    • MongoDB 3.6 -> MongoDB 4.0
    • MongoDB 4.0 -> MongoDB 4.2

Note

If you have enabled backup for your cluster and want to upgrade to MongoDB 4.2, you:

Scale your Replica Set to a Sharded Cluster

Note

Sharded clusters running MongoDB 4.2 must use Cloud Provider Snapshots.

To deploy your cluster as a sharded cluster, toggle Shard your cluster (M30 and up) to Yes.

For more information on deploying a sharded cluster, see Deploy a Sharded Cluster.

Modify the Number of Shards

This field is visible only if the deployment is a sharded cluster.

You can set the number of shards to deploy with the sharded cluster. Your cluster can have between 1 and 50 shards, inclusive.

Note

A sharded cluster with a single shard is not recommended for production environments. Single-shard sharded clusters do not provide the same high availability and horizontal scaling benefits as configurations with multiple shards.

Enable or Disable Backup for the Cluster

Backups are automatically enabled for M2 and M5 shared-tier clusters and cannot be disabled. For more information, see M2/M5 Snapshots.

To enable backups for an M10+ Atlas cluster, toggle Turn on Backup (M10 and up) to Yes. If enabled, Atlas takes snapshots of your databases at regular intervals and retains them according to your project’s retention policy.

For detailed descriptions of the available backup options, see Configure Backup Options for the Cluster.

Enable or Disable BI Connector for Atlas for the Cluster

To enable BI Connector for Atlas for this cluster, toggle Enable Business Intelligence Connector (M10 and up) to Yes.

For more information on the BI Connector for Atlas, see Enable BI Connector for Atlas.

Enable Encryption at Rest

To enable Atlas Encryption at Rest for this cluster, toggle Encryption At Rest with WiredTiger Encrypted Storage Engine (M10 and up) to Yes.

For more information on Atlas Encryption at Rest, see Manage Your Own Encryption Keys.

Configure Additional Configuration Options

Configure additional options for your cluster from this section.

For details on these options, see Configure Additional Options.

Confirm and Deploy Your Changes

Click Confirm & Deploy deploy your changes.

If you are upgrading from an M0 Free Tier cluster, Atlas prompts you to enter payment information before deploying your changes.

[1]For replica sets, the data-bearing servers are the servers hosting the replica set nodes. For sharded clusters, the data-bearing servers are the servers hosting the shards. For sharded clusters, Atlas also deploys servers for the config servers; these are charged at a rate separate from the cluster costs.