Fix Storage Issues

Disk Space % Used alerts indicate the percentage of used disk space on a partition reaches a specified threshold.

Alert Conditions Configured by Default

Atlas configures the following alert conditions by default to help you ensure dedicated cluster availability and prevent the cluster from going down due to disk exhaustion on the primary node and to maintain read availability.

Writes have been blocked on your cluster due to critically low disk space occurs when the percentage of used disk has exceeded write-blocking-thresholds, and Atlas has blocked writes to maintain read availability.
You can view disk metrics through Real-Time Performance Panel and review MongoDB process metrics.
Writes have been unblocked on your cluster occurs when the percentage of used disk on the primary node has fallen below the unblocking thresholds, and Atlas automatically unblocks writes to the cluster. See also Unblocking Writes.
This is an information-only alert that doesn't require any action on your part. To prevent future write-blocking events, we recommend that you monitor your cluster's disk usage. To learn more, see Preventing Write-Blocking.

Alert Conditions You Can Configure

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

Disk space % used on Data Partition occurs when the percentage of disk space used on any partition that contains the MongoDB collection data meets or exceeds a certain threshold. By default, the threshold is 90 percent of the cluster's configured storage size.

Common Triggers

The following common events can trigger Disk Space % Used alerts:

The percentage of used disk has exceeded write-blocking-thresholds, and Atlas has blocked writes to maintain read availability.
The disk is full and Auto-Expand Storage is not enabled.
Auto-Expand Storage is enabled, but the disk filled too quickly for Atlas to expand the cluster's storage space. This can happen during data migration.
Auto-Expand Storage is enabled, but Atlas cannot expand the cluster's storage space because it has reached the maximum storage capacity for this cluster. For more information on cluster tier limits, see the Amazon Web Services, Google Cloud Platform, and Microsoft Azure instance configuration options.

Fix the Immediate Problem

Consider the following actions to help resolve Disk Space % Used alerts through the Atlas UI or API.

Enable Auto-Expand Storage.
Note
If the disk fills too quickly, Atlas might not be able to expand the cluster's storage space in time, even if Auto-Expand Storage is enabled.
Manually increase the Storage of this cluster in the Cluster Tier section of the configuration page.

Enable Auto-Expand Storage using the autoScaling.diskGBEnabled parameter.
Note
If the disk fills too quickly, Atlas might not be able to expand the cluster's storage space in time, even if Auto-Expand Storage is enabled.
Increase the storage of this cluster using the diskSizeGB parameter.

Implement a Long-Term Solution

Consider the following long-term solutions to help resolve Disk Space % Used alerts through the Atlas UI or API.

If you have reached the maximum storage capacity for this cluster, upgrade to a larger cluster tier in the Cluster Tier section of the configuration page.

If you have reached the maximum storage capacity for this cluster, specify a larger cluster tier using the providerSettings.instanceSizeName parameter.

Monitor Your Progress

You can observe a high percentage of used disk space in the following ways:

In the cluster metrics, the Disk Usage graph displays the used disk space in yellow. This indicates that the used disk space is approximately 70 percent of the Atlas cluster's configured storage size.
Atlas nodes are unhealthy, because the used disk space reached the cluster's configured storage size.
The cluster blocks writes and connections from the client.

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