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Atlas M0 (Free Tier), M2, and M5 Limitations

Atlas M0 (Free Tier), M2, and M5 Limitations¶

Configuration Limitations¶

The following table lists the configuration limitations of Atlas M0 Free Tier and M2/M5 shared clusters:

Configuration Option	Limitation
Cloud Service Provider and Region	`M0` Free Tier clusters and `M2/M5` shared clusters are only deployable in a subset of regions on AWS, GCP, and Azure. For more information on which cloud provider regions support free and shared tiers, see: Amazon Web Services (AWS) Google Cloud Project (GCP) Microsoft Azure
MongoDB Version and Storage Engine	Atlas locks the MongoDB version and storage engine for `M0/M2/M5` clusters to MongoDB 4.0 with WiredTiger.
Instance Size	You must select the `M0` instance size to deploy a Free Tier cluster.
Instance Memory	You cannot configure memory for `M0` Free Tier or `M2/M5` shared clusters.
Instance Storage	You cannot configure storage size for `M0` Free Tier or `M2/M5` shared clusters.
Replication Factor	Replication Factor is set to `3 Nodes` and cannot be modified for `M0` Free Tier, or `M2/M5` shared clusters.
Replica Set Tags	`M0` Free Tier, and `M2/M5` shared clusters are not configured with pre-defined replica set tags.
Do You Want A Sharded Cluster	You cannot deploy a `M0` Free Tier or `M2/M5` shared cluster as a Sharded Cluster.
Do You Want To Enable Backup	You cannot enable backups on `M0` Free Tier or `M2/M5` shared clusters. Backup Alternative: mongodump You may use mongodump to back up your data and mongorestore to restore that data. To learn how to manually back up your data, see Command Line Tools.
Test Failovers	You cannot perform primary failover testing on `M0` Free Tier or `M2/M5` shared clusters.
Database Auditing	You cannot configure database auditing on `M0` Free Tier or `M2/M5` shared clusters.
Encryption at Rest using your Key Management	You cannot configure Encryption at Rest Using Your Key Management on `M0` Free Tier or `M2/M5` shared clusters.

Operational Limitations¶

The following table lists the operational limitations of Atlas M0 Free Tier and M2/M5 shared clusters:

Configuration Option	Limitation
Aggregation	Atlas `M0` Free Tier clusters do not support the `allowDiskUse` option for the aggregation command or its helper method.
Throughput	Maximum of 100 operations per second allowed for `M0` Free Tier and `M2/M5` shared clusters.
Query Utilization	The percentage of time that a query is running over any five minute period must remain under 100% on `M0` Free Tier and `M2/M5` shared clusters .
Connections	`M0` Free Tier and `M2/M5` shared clusters are allowed a maximum of 100 connections.
Data Transfer Limits	`M0/M2/M5` clusters limit the total data transferred into or out of the cluster as follows: `M0`: 10 GB per week `M2`: 20 GB per week `M5`: 50 GB per week Atlas throttles the network speed of clusters which exceed the posted limits.
JavaScript	`M0` Free Tier and `M2/M5` shared clusters do not support server-side JavaScript. Example $where and map-reduce are not supported.
API Access	You cannot modify or configure an `M0` Free Tier cluster using the Clusters API endpoint. A subset of API endpoints support `M2` and `M5` shared clusters.
Number of Free Tier clusters	You can deploy at most one `M0` Free Tier cluster per Atlas project.
Database Commands	Certain database commands are unsupported or behavior differently in an `M0` Free Tier cluster. To learn more, see Command Limitations in Free Tier Clusters. Please contact Atlas support for any questions or comments related to restricted commands.
Atlas Monitoring	The Metrics view of an `M0` Free Tier or `M2/M5` shared cluster only displays the following metrics: Connections Logical Size Network Opscounter For more information on these metrics, see Real Time Metrics.
Atlas Alerts	`M0/M2/M5` clusters can only trigger alerts configured with one of the following alert conditions: Connections Logical Size Network Opscounter
Namespaces and Database Names	`M0` Free Tier and `M2/M5` shared cluster namespaces are limited to 95 bytes. Database names are limited to 38 bytes.
Database and Collections	`M0` Free Tier and `M2/M5` shared clusters have a maximum of 100 databases and 500 collections total.
Database Logs	`M0` Free Tier and `M2/M5` shared clusters do not provide downloadable logs.
Cluster Persistance	Atlas may terminate idle `M0` Free Tier clusters as per the Terms of Service.
Auto-Expand Storage	`M0` Free Tier and `M2/M5` shared clusters do not provide automatically scaling storage.
Performance Advisor	`M0` Free Tier and `M2/M5` shared clusters do not provide access to the Performance Advisor.
Real-Time Performance Panel	`M0` Free Tier and `M2/M5` shared clusters do not provide access to the Real-Time Performance Panel.
Build Index with Rolling Build	`M0` Free Tier and `M2/M5` shared clusters do not provide the ability to build indexes with a rolling build.
Custom Roles	Changes to custom roles make take up to 30 seconds to deploy in `M0` Free Tier and `M2/M5` shared clusters.

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