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Fix CPU Usage Issues

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  • Alert Conditions
  • Common Triggers
  • Fix the Immediate Problem
  • Implement a Long-Term Solution
  • Monitor Your Progress

System CPU alerts indicate that the CPU usage of the MongoDB process has reached a specified threshold. This threshold is specified when the alert is created.

You can configure the following alert conditions in the project-level alert settings page to trigger alerts.

System: CPU (Steal) % is occurs when the CPU usage exceeds the guaranteed baseline CPU credit accumulation rate by the specified threshold. For more information on CPU credit accumulation, refer to the AWS documentation for Burstable Performance Instances.


The System: CPU (Steal) % is alert is applicable when the EC2 instance credit balance is exhausted. Atlas triggers this alert only for AWS EC2 instances that support Burstable Performance Instances. Currently, these are M10 and M20 cluster types.

System: CPU (User) % is occurs when the CPU usage of the MongoDB process, as normalized by the number of CPUs, exceeds the specified threshold.

Unoptimized queries might lead to System CPU alerts. Also, your current cluster tier might not support the current workload.

Consider adding one or more indexes to improve query performance.

Consider upgrading your cluster to a higher tier to reduce the CPU usage percentage utilized by the current workload. For more information on upgrading a cluster, see Modify a Cluster.

View the Normalized System CPU chart to monitor CPU usage of all processes on the node, scaled to a range of 0-100% by dividing by the number of CPU cores.

Monitor CPU usage to determine whether data is retrieved from disk instead of memory.

If you are unable to see the usage that triggered the alert, zoom in on the Normalized System CPU chart by clicking and dragging your mouse over the period of interest. With a higher-resolution view you may be able to identify acute spikes in CPU usage that weren't visible in the overview.

To learn more, see View Cluster Metrics.

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