Atlas Replica Sets

A replica set in MongoDB is a group of mongod processes that maintain the same data set. To view the metrics for a specific Atlas cluster in the Clusters view of a project, click the Metrics button for that cluster. Alternatively, click on the name of the cluster to open the cluster overview, then click the Metrics tab. You can look at your replica set holistically, or hone in on a specific node.

Monitor cluster metrics to identify performance issues and determine whether your current cluster tier meets your requirements.

The Metrics view has three distinct sections:

Monitoring Data Storage Granularity

Atlas stores metrics data at increasing granularity levels. For more information, see Monitoring Data Storage Granularity.

Atlas provides the following controls for the Metric view. Adjusting any of these options affects all charts displayed under the Metrics view:

Modifies the granularity of metrics displayed for each chart. Select a granularity between 1 minute and 1 day (24 hours). Select Auto to automatically adjust the granularity based on the selected Zoom or Current Display date controls. Auto granularity selects the highest fidelity granularity available for the time range.
Modifies the date range of metrics displayed for each chart. Select a zoom range between 1 hour and 5 years. Adjusting the Zoom automatically adjusts the Current Display date range.
Current Display
Modifies the start and end date-time range of metrics displayed for each chart. Modifying the start and end date sets the value of Zoom to custom and overrides the previously selected zoom level.
Toggle Members
Limit charts to the selected replica set members. The P icon represents the primary replica set member, while the S icon represents a secondary member.
Add Chart
Select one or more charts to display or hide. Adding charts using this dropdown is identical to adding charts from the Toggle Charts section of the Metrics view.
Display Opcounters on Separate Charts
Directs Atlas to split the Opcounters chart into its individual components. You can then choose to chart one or more of those components.
Display Timeline Annotations
Directs Atlas to display or hide chart annotations. Chart annotations consist of colored vertical lines that indicate server events, such as a server restart or a transition in member state.

When viewing charts, you can do the following:

View a detailed description of a chart.

Hover your mouse over the chart to display the context menu.

Click next to the chart name to open the Chart Info modal. This modal includes a breakdown of the chart's data series, the annotations available for that chart, and the operations the chart supports.

Expand a chart.

Hover your mouse over the chart to display the context menu.

Click the two-way arrow at the top right of the chart.

Zoom in on a period of time.

Click and drag the mouse pointer over a portion of the chart.

To reset to the originally selected range (zoom out), double-click the chart.


When you zoom in on one period of time, the Current Display date range in the chart control section automatically updates to reflect the selected period.

View statistics at a particular time.
Hover the mouse pointer over a point on the chart.
Move a chart.
Click and hold the grabber in the upper left corner of the chart, and drag the chart to the new position.
Share a URL to the chart.

Hover your mouse over the chart to display the context menu.

Click the curved arrow on the chart. Select Chart Permalink to retrieve a URL to the chart. Select Email Chart to email the chart.

The recipient of the chart URL must have a Atlas user account with access to the project and cluster.

Atlas displays the available metrics to chart for the selected cluster under the Toggle Charts header. Metrics are grouped into two sections:

MongoDB Metrics

Metrics associated with the MongoDB process. For metrics related to database performance, such as DB Storage, Atlas presents the sum total across all databases in the cluster.

If you enable Display Opcounters on Separate Charts, Atlas replaces the Opcounters option with the individual components of that chart.

Hardware Metrics

Metrics associated with the host machines supporting the cluster.

Charts marked with the + symbol are inactive, while charts marked with the - symbol are active. Click on any chart to toggle the chart state.

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