Atlas Service Limits
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Atlas limits how many of each kind of component you can create, and the number of connections allowed to clusters. For clusters, the number of connections allowed is based on cluster tier. The following tables outline component and connection limits.
Important
If any of these limits present a problem for your organization, contact Atlas support.
Cluster Limits
Component | Limit |
|---|---|
12 | |
Shards in Single-region clusters | No hard limit, but contact MongoDB Support for more than 70 shards. |
Cross-region network permissions for a Multi-Region Cluster | 40 If any project's cluster spans more than 40 regions, you can't create a multi-region cluster in this project. |
Electable Nodes per Replica Set or Shard | 7 |
Config Server Tier (minimum and maximum) |
|
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.
Example
Your M10 cluster has three nodes with a 1500 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 2980 connection limit.
Increase Connection Limit
If you need to increase the number of connections your Atlas cluster can handle, consider upgrading your cluster tier.
If your application dynamically creates additional connections, as it might if, for example, your database worker pool is elastic, consider enabling Cluster Autoscaling to ensure that your Atlas cluster can accomodate your dynamic connection count requirement.
Cluster Tier | Maximum Connections Per Node |
|---|---|
| 1500 |
| 3000 |
| 3000 |
| 6000 |
| 16000 |
| 32000 |
| 96000 |
| 96000 |
| 128000 |
| 128000 |
Cluster Tier | Maximum Connections Per Node |
|---|---|
| 4000 |
| 16000 |
| 32000 |
| 64000 |
| 96000 |
| 128000 |
| 128000 |
| 128000 |
| 128000 |
Cluster Tier | Maximum Connections Per Node |
|---|---|
| 1500 |
| 3000 |
| 3000 |
| 6000 |
| 16000 |
| 32000 |
| 64000 |
| 96000 |
| 128000 |
| 128000 |
Note
Atlas reserves a small number of connections to each Atlas cluster for supporting Atlas services. To learn more about Atlas reserved connections, contact Atlas support.
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 |
Increase Collection and Index Limits
If you need to increase the number of collections or indexes in your Atlas cluster, consider upgrading your cluster tier.
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 |
Linked Organizations per Atlas Paying Organization | 50 |
Clusters per Atlas Project | 25 |
Projects per Atlas User | 250 |
Projects per Atlas Organization | 250 |
Custom MongoDB roles per Atlas Project | 100 |
Assigned Roles per Database User | 100 |
Federated database instances per Atlas Project | 25 |
Total Network Peering Connections per Atlas Project | 50 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 |
Google Cloud GCP Private Service Connect Addressable Targets per Region | 50 |
Global Cluster shard keys per Atlas Project | 40 |
You can deploy only one M0 cluster per
project. However, if you have sales contracts with MongoDB, you might
be able to deploy more M0 clusters per project. To learn more,
contact a MongoDB sales representative.
Label Limits
Atlas limits the length of particular labels for components.
Component | Character Limit | RegEx Pattern |
|---|---|---|
Cluster Name | 64 [1] |
|
Project Name | 64 |
|
Organization Name | 64 |
|
API Key Description | 250 |
| [1] | If you have peering-only mode enabled, the cluster name character limit is 23. |
| [2] | Atlas uses the first 23 characters of a cluster name.
These characters must be unique within the containing project.
Cluster names with fewer than 23 characters can't end with a hyphen
(-). Cluster names with more than 23 characters can't have a
hyphen as the 23rd character. |
| [3] | (1, 2) Organization and Project names can include any Unicode letter or
number plus the following punctuation: -_.(),:&@+'. |
Database User Privilege Limits
To learn more about unsupported commands, see the unsupported commands for Unsupported Commands in M0/M2/M5 and Atlas Flex Clusters and paid clusters.
Multi-Cloud Deployment Limits
Multi-cloud deployments have different limits. To learn more, see Multi-Cloud Deployment Limits.