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Create a Cluster

This tutorial takes you through the steps to create a new Atlas cluster. To learn how to modify an existing Atlas cluster, see Modify a Cluster.

Clusters can be either a replica set or a sharded cluster. This tutorial walks you through creating a replica set.

To create a cluster, you must have Organization Owner or Project Owner access to the project.

  • To minimize network latency and data transfer costs, and to increase overall stability and security, use the same cloud provider and region to host your application and cluster when possible.

  • Clusters can span regions and cloud service providers. The total number of nodes in clusters spanning across regions has a specific constraint on a per-project basis.

    Atlas limits the total number of nodes in other regions in one project to a total of 40. This total excludes:

    • Google Cloud regions communicating with each other

    • Free clusters or shared clusters

    • Serverless instances

    The total number of nodes between any two regions must meet this constraint.

    Example

    If an Atlas project has nodes in clusters spread across three regions:

    • 30 nodes in Region A

    • 10 nodes in Region B

    • 5 nodes in Region C

    You can only add 5 more nodes to Region C because:

    1. If you exclude Region C, Region A + Region B = 40.

    2. If you exclude Region B, Region A + Region C = 35, <= 40.

    3. If you exclude Region A, Region B + Region C = 15, <= 40.

    4. Each combination of regions with the added 5 nodes still meets the per-project constraint:

      • Region A + B = 40

      • Region A + C = 40

      • Region B + C = 20

    You can't create a multi-region cluster in a project if it has one or more clusters spanning 40 or more nodes in other regions.

    Contact Atlas support for questions or assistance with raising this limit.

  • Each Atlas project supports up to 25 database deployments. Please contact Atlas support for questions or assistance regarding the database deployment limit. To contact support, select Support from the left-hand navigation bar of the Atlas UI.

  • If your Atlas project contains a custom role that uses actions introduced in a specific MongoDB version, you must delete that role before creating clusters with an earlier MongoDB version.

  • Atlas clusters created after July 2020 use TLS version 1.2 by default.

  • When you create a cluster, Atlas creates a network container in the project for the cloud provider to which you deploy the cluster if one does not already exist.

  • If you have a Backup Compliance Policy enabled, all new and existing clusters have Cloud Backup automatically enabled and use the project-level Backup Compliance Policy. Atlas augments any preexisting cluster-level policies to meet the minimum requirements of the Backup Compliance Policy. All new clusters use the Backup Compliance Policy unless the mininum requirements of the cluster-level backup policy expand beyond the mininum requirements of the Backup Compliance Policy.

[1](1, 2) 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.
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