Atlas Limitations¶
Atlas limits how many of each kind of component you can create, and the number of connections allowed to a cluster based on cluster tier. These tables outline component and connection limits.
If any of these limits present a problem for your organization, please contact Atlas support.
Cluster Limits¶
| Component | Limit |
|---|---|
| Shards in Multi-Region Clusters | 12 |
| Shards in Single-region clusters | 50 |
| Total Nodes per Region of a Multi-Region Cluster | 40 |
| Electable Nodes per Region | 7 |
| Config Server Tier (minimum and maximum) | M30 |
Connection Limits and Cluster Tier¶
Atlas sets the limits for concurrent incoming connections based on the cluster tier and
class:
| Cluster Tier | Maximum Connections |
|---|---|
M0 | 500 |
M2 | 500 |
M5 | 500 |
M10 | 1500 |
M20 | 3000 |
M30 | 3000 |
M40 | 6000 |
M50 | 16000 |
M60 | 32000 |
M80 | 64000 |
M140 | 96000 |
M200 | 128000 |
M300 | 128000 |
Atlas reserves a small portion of connections to each Atlas cluster for supporting Atlas services. Contact Atlas support for more information on Atlas reserved connections.
Collection and Index Limits¶
While there is no hard limit on the number of collections in a single cluster, the performance of a cluster might degrade if it serves a large number of collections and indexes. Larger collections have a greater impact on performance.
The recommended maximum combined number of collections and indexes by Atlas cluster tier are as follows:
| Cluster tier | Recommended maximum |
|---|---|
| M10 | 5,000 collections and indexes |
| M20 / M30 | 10,000 collections and indexes |
| M40+ | 100,000 collections and indexes |
Organization and Project Limits¶
| Component | Limit |
|---|---|
| Total Network Peering Connections per Atlas Project | 50 Note Atlas limits the number of nodes per Network Peering connection based on the CIDR block and the region selected for the project. |
| Pending Network Peering Connections per Atlas Project | 25 |
| Database Users per Atlas Project | 100 |
| Atlas Users per Atlas Project | 500 |
| Atlas Users per Atlas Organization | 500 |
| API Keys per Atlas Organization | 500 |
| Access List Entries per Atlas Project | 200 |
| Users per Atlas Team | 250 |
| Teams per Atlas Project | 100 |
| Teams per Atlas Organization | 250 |
| Teams per Atlas User | 100 |
| Organizations per Atlas User | 250 |
| Clusters per Atlas Project | 25 |
| Projects per Atlas Organization | 250 |
| Custom MongoDB roles per Atlas Project | 100 |
| Assigned Roles per Database User | 100 |
| Hourly Billing per Atlas Project | $50 Note A Technical Account Manager or Billing Admin can raise this limit. |
| Data Lake Tenants per Atlas User | 25 |
Label Limits¶
Atlas also limits how long particular labels of components can be.
| Component | Character Length Limit |
|---|---|
| Cluster Name | 64 Important Atlas truncates the cluster name to 23 characters in its internal interactions. In practice, this means:
|
| API Key Description | 250 |