Cluster Tier

The cluster tier dictates the memory, storage, and IOPS specification for each data-bearing server [1] in the cluster.

Image showing the cluster tier selection.

Shared Clusters

Shared clusters are sandbox replica set clusters for getting started with MongoDB. These clusters deploy to a shared environment with access to a subset of Atlas features and functionality. For complete documentation on shared cluster limits and restrictions, see Atlas M0 (Free Tier), M2, and M5 Limitations.

Atlas provides an option to deploy one M0 Free Tier replica set per project. You can upgrade an M0 Free Tier cluster to an M2+ paid cluster at any time.

M2 and M5 clusters are low-cost shared starter clusters. These clusters provide the following additional features and functionality compared to M0 clusters:


Dedicated Clusters for Low-Traffic Applications

These cluster tiers support development environments and low-traffic applications.

These clusters support replica set deployments only, but otherwise provide full access to Atlas features and functionality.


MongoDB recommends M10 and M20 clusters for

  • Development environments
  • Low-traffic production use

When M10 and M20 clusters hosted on AWS experience periods of high usage, they can temporarily increase performance through bursting. During periods of low usage, M10 and M20 clusters accumulate EC2 instance credits, and these credits are depleted when bursting occurs. The System: CPU (Steal) % is alert is triggered when the EC2 instance credit balance is exhausted.

Dedicated Clusters for High-Traffic Applications

M30 and higher cluster tiers support production environments with high traffic applications and large datasets.

These clusters support replica set and sharded cluster deployments with full access to Atlas features and functionality.

Some clusters have variants, denoted by the ❯ character. When you select these clusters, Atlas lists the variants and tags each cluster to distinguish their key characteristics.

NVMe Storage on AWS Clusters

For applications hosted on AWS which require low-latency and high-throughput I/O, Atlas offers storage options which leverage locally attached ephemeral NVMe SSDs. The following cluster tiers have an NVMe option, with the size fixed at the cluster tier:

  • M40
  • M50
  • M60
  • M80
  • M200
  • M400

Clusters with NVMe storage use Cloud Provider Snapshots for backup. You can’t disable backup on NVMe clusters.

NVMe clusters use a hidden secondary node consisting of a provisioned volume with high throughput and IOPS to facilitate backup.


NVMe clusters auto-scale to the next higher tier when 90% of the available storage space is consumed, and the migration requires an initial sync.

Free, Shared, and Dedicated Cluster Comparison

The following table highlights key differences between an M0 Free Tier cluster, an M2 or M5 shared starter cluster, and an M10+ dedicated cluster.

  Free Tier Cluster (M0) Shared Starter Cluster (M2 and M5) Dedicated Cluster (M10 and larger)
Storage (Data Size + Index Size)
512 MB
M2: 2 GB
M5: 5 GB
10 - 4000 GB
MongoDB Version Support 4.0 4.0 3.6, 4.0, 4.2
Metrics and Alerts Limited Limited Full metrics, including the Real Time Performance Tab, and full alert configuration options.
VPC Peering No No VPC Peering Connection wizard
Global Region Selection Atlas supports deploying M0 clusters in a subset of regions in AWS, GCP, and Azure. Atlas supports deploying M2 and M5 clusters in a subset of regions in AWS, GCP, and Azure. Atlas supports deploying clusters globally on Amazon Web Services, Google Cloud Platform, and Microsoft Azure
Cross-Region Deployments No No Yes. Specify additional regions for high availability or local reads when creating or scaling a cluster.
Backups No Yes, daily backup snapshots Yes, including queryable backups
Sharding No No Yes, for clusters using an M30+ tier
Dedicated Cluster No, M0 Free Tier clusters run in a shared environment No, M2 and M5 clusters run in a shared environment Yes, M10+ clusters deploy each mongod process to its own instance.
Performance Advisor No No Yes
BI Connector for Atlas No No Yes

For a complete list of M0 (Free Tier), M2, and M5 limitations, see Atlas M0 (Free Tier), M2, and M5 Limitations.

[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.