FAQ: Deployment

MongoDB Atlas or MongoDB Cloud Manager?

Atlas offers a managed and simplified experience. Atlas users have access to a curated selection of configuration and infrastructure options. The available Atlas configuration and infrastructure options may not provide the flexibility that some users require. For example, Atlas requires TLS for cluster connectivity and does not surface options for disabling TLS. Atlas suits users who want fewer moving parts to manage, enabling developers and database administrators to be more productive.

MongoDB Cloud Manager offers more control by exposing more configuration options on the infrastructure of your choice. Cloud Manager users have access to advanced operations and a higher level of control, but must manage the full lifecycle of their infrastructure. Cloud Manager is best suited for users who require a higher level of control over their MongoDB clusters.

For guidance on which MongoDB service best suits the needs of your organization, contact MongoDB Support.

Can I bring an existing MongoDB deployment into MongoDB Atlas for management?

No. However, you can upload data from existing MongoDB deployment into MongoDB Atlas.

• You can use the Live Migrate feature in Atlas to migrate from a source replica set to an Atlas replica set cluster.
• You can use the Live Migrate feature in Atlas to migrate from a source sharded cluster to an Atlas sharded cluster.
• You can use mongomirror to migrate data from an existing MongoDB replica set into MongoDB Atlas.
• You can use mongodump and mongorestore to seed MongoDB Atlas clusters from an existing standalone, replica set, and sharded cluster.

To learn more, see Migrate or Import Data.

You can also write scripts using official MongoDB supported drivers to upload data.

Can I migrate between regions?

Yes. You can change one or more regions for a given cluster within the original cloud service provider for that cluster. Using a rolling-migration strategy for moving nodes from the original region to a new region, MongoDB Atlas preserves cluster availability.

If you need to migrate data between regions on different cloud service providers, you can:

• Perform live migration, or
• Migrate using mongomirror, or
• Seed the destination cluster using mongorestore, or
• Restore a backup from the source cluster to the destination cluster.

Does Atlas support cross-region deployments?

Yes. You can specify additional regions for high availability or local reads when creating or scaling a deployment.

Atlas supports cross-cloud service provider deployments. To learn more, see Electable Nodes for High Availability.

What AWS regions does Atlas support?

Atlas supports all AWS regions other than those in China and US GovCloud. To learn more, see Amazon Web Services (AWS).

Can I pause or stop my Atlas clusters?

You can pause an M10+ paid cluster for up to 30 days at a time. Atlas automatically resumes the cluster after 30 days.

Can I pre-split chunks in a Atlas sharded cluster?

The Atlas admin database user role has the necessary privileges to pre-split chunks in an empty sharded collection.

To learn more about sharded cluster chunk creation and management, see Create Chunks in a Sharded Cluster.

Can MongoDB Atlas deploy clusters with more than 50 shards?

While MongoDB Atlas out of the box allows selection of up to 50 shards, customers interested in more than 50 shards should inquire with MongoDB. Contact MongoDB Support.

How does MongoDB Atlas deliver high availability?

Atlas clusters use MongoDB's replication capability to deliver high availability. All Atlas clusters are either replica sets or sharded clusters where each shard is a replica set. For complete documentation on MongoDB replica sets and replication, see Replication.

Atlas uses a rolling upgrade strategy for executing maintenance or infrastructure operations, such as applying security patches or scaling up a Atlas cluster. The rolling upgrade strategy ensures that the cluster can process reads and writes for the majority of the maintenance or infrastructure operation. During the rolling upgrade procedure:

• Atlas applies the changes to each secondary node in the cluster.
• Atlas directs the primary node to step down to the secondary state and trigger an election of a new primary.
• Once the cluster has a new primary, Atlas applies the changes to the former primary node.

Applications must hold write operations while the cluster elects a new primary. The cluster can continue to process secondary read operations during this period. Elections on Atlas clusters typically complete within a few seconds. Factors such as network latency may extend the time required for replica set elections to complete, which in turn affects the amount of time your cluster may operate without a primary. These factors are dependent on your particular cluster architecture.

For M10+ clusters, Atlas provides a Test Failover feature for application developers to check that their applications are designed to detect and react appropriately to a replica set election. By designing applications that can seamlessly handle a replica set election, developers no longer have to worry about the underlying maintenance occurring on their clusters.

Atlas maintenance operations include OS patches and maintenance patches for the MongoDB database itself, such as v4.2.3 to v4.2.4. Infrastructure operations include repair operations required to replace faulty infrastructure, and scheduled infrastructure replacements such as changing the cluster tier.

Please contact MongoDB Support if you would like help architecting your application to use MongoDB Atlas with optimal availability.

What are Analytics Nodes?

Available on M10+ clusters.

Analytics nodes are specialized read-only nodes used to isolate queries which you do not want to affect your operational workload. They are useful for handling analytic data such as reporting queries executed by BI tools.

Analytics nodes and read-only nodes are configured with distinct replica set tags that allow you to direct queries to desired node types and regions. For details on the pre-defined replica set tags implemented by Atlas, see Atlas Replica Set Tags.

You can have up to 50 total nodes on a multi-region cluster. Within that limit there's no maximum number of analytics nodes.

Analytics nodes cannot contribute to a cluster's availability because they cannot participate in elections, or become the primary for their cluster.