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Review Sharded Clusters

On this page

  • Chart Controls
  • Chart Display
  • Data Sources

A sharded cluster is the set of nodes comprising a sharded MongoDB deployment. To view the metrics for a specific Atlas cluster in a project, click the View Monitoring button for that cluster. Alternatively, click on the name of the cluster to open the cluster overview, then click the Metrics tab.

The Metrics tab for sharded clusters provides a side-by-side comparision of shards in one view. The Display drop-down contains many available metrics.

Monitor cluster metrics to identify performance issues and determine whether your current cluster meets your requirements. For more information on the metrics available to monitor your clusters, see Review Available Metrics.

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:


Modifies the granularity of metrics displayed for each chart. Select a granularity, usually 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 within the selected time range and sharded cluster metric rendering limits.


Sharded Cluster Metric Rendering Limits

In the Sharded Cluster metrics view, Atlas renders a maximum of:

  • 100,000 total data points and

  • 3,000 data points for a single series.

As a result, when rendering metrics for large deployments over a long period of time, Atlas may display metrics at a lower granularity than expected. To learn more about the granularity at which Atlas stores metric data, see Monitoring Data Storage Granularity.


Atlas supports a 10 second granularity only on M40 and larger clusters. To learn more, see Premium Monitoring Granularity.

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.
Selects which metric to chart. You can display no more than one chart at a time.
Display Data

Directs Atlas to display data based on the selected option

  • Individually - displays the selected metrics for each shard as an individual line.

  • Sum - displays the sum of the selected metrics across all shards in the cluster.

  • Averaged - displays the average of the selected metrics across all shards in the cluster.


Selects which sharded cluster components to display

  • SHARDS - displays metrics for each shard in the sharded cluster.

  • MONGOS - displays metrics for each mongos in the sharded cluster.

  • CONFIGS - displays metrics for the config server in the sharded cluster config server replica set.

When viewing charts, you can do the following:

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.

Atlas displays each data source that contributes to the metric chart in a table below the chart. The table consists of the following:

Shard Name

When View is set to SHARDS, displays the name of each shard in the sharded cluster.

When View is set to MONGOS or CONFIGS, displays the name of each mongos or config server mongod process in the cluster.

Click on a listed component to open the Metrics view for that component.

Indicates if there are any open alerts for the listed shard or process. Click on the alert icon to open the Alerts view for that shard or process. For more information on responding to open alerts, see Resolve Alerts.
Data Size

Only visible if View is set to SHARDS.

Indicates the logical size of all documents and indexes on the shard.


Only visible if View is set to SHARDS

Indicates which replica set members to show on the selected chart. Select Primaries, Secondaries or All.

Read, Write, and Queued
Metric data related to the displayed chart. Hover over the corresponding column for a pop up with detailed information on the metrics shown.
← Replica Sets