Atlas Limitations¶
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Atlas limits how many of each kind of component you can create, and the number of connections allowed to a database deployments. For clusters, the number of connections allowed is 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 |
|---|---|
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. Atlas connection limits apply per node. For
sharded clusters, Atlas connection limits apply per
mongos router. The number of
mongos routers is equal to
the number of replica set nodes across all shards.
Your read preference also contributes to the total number of connections Atlas can allocate for a given query.
Your M2 cluster has three nodes with a 500 connection limit per node. Atlas reserves 10 connections per node. If you set your read preference to secondary, Atlas can read from the two secondary nodes for a combined 980 connection limit.
Atlas reserves a small number 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 |
|---|---|
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 |
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 |
AWS PrivateLink Addressable Targets per
Region | 50 |
Azure Private Link Addressable Targets per
Region | 150 |
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:
|
Project Name | 64 |
Organization Name | 64 Latin alphanumeric characters only. |
API Key Description | 250 |
Database User Privilege Limits¶
To learn more about unsupported commands, see the unsupported commands for free or shared clusers, paid clusters, and serverless instances
Serverless Instance Limits¶
Serverless instances have different limitations. To learn more, see Serverless Instance Limitations.