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Resolve Alerts

Fix IOPS Issues

On this page

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

System and disk alert conditions can indicate IOPS issues.

Note

All hardware metrics have burst reporting equivalents with distinct configurable alerts. To learn more, see Burst Reporting.

Alert Conditions

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

The Disk read IOPS on Data Partition is alert condition is raised if the average number of disk read operations per second exceeds the specified threshold.

The Disk write IOPS on Data Partition is alert condition is raised if the average number of disk write operations per second exceeds the specified threshold.

System: CPU (User) % is measures the CPU usage of the processes on the node, normalized by the number of CPUs. This value is scaled to a range of 0-100%.

Common Triggers

A few common events may trigger these alerts:

  • Unoptimized queries.

  • A one-time event, such as an index build.

Fix the Immediate Problem

Consider a few possible actions to help resolve these alerts:

  • Optimize your queries.

  • Use the Atlas Performance Advisor to view slow queries and suggested indexes.

  • Review Indexing Strategies for possible further indexing improvements.

    Note

    You might need to temporarily increase your cluster IOPS to create new indexes. Provisioned IOPS is supported only for M30+ tier AWS clusters.

To change a cluster's IOPS, go to the Cluster Configuration page and do the following possible actions:

Cloud Provider
Tier
Possible Actions

AWS

M10, M20

AWS

M30 or larger

Google Cloud

M10 or larger

Azure

M10 or larger

Implement a Long-Term Solution

Disk IOPS Burst Credits for Atlas Clusters on Azure

Atlas clusters deployed to Azure may use credit-based bursting, but the disk will burst only if it has burst credits accumulated in its credit bucket. Azure also offers an on-demand bursting model, where the disk bursts whenever its needs exceed its current capacity.

See the Azure Disk Bursting documentation for more information about how bursting for Azure disks works.

Conserve Burst Credits

If you regularly exceed your configured IOPS threshold, you can avoid depleting your burst credits by increasing your configured IOPS with any of the following actions:

  • Increase Cluster IOPS to increase the cluster's IOPS threshold.

  • Increase Storage Capacity. The IOPS threshold increases as you increase storage capacity. Clusters configured to use at least 1 TB of storage have baseline IOPS performance that is equal to or greater than the maximum burst performance. These volumes do not deplete burst credit balances.

  • Upgrade Cluster Tier. Larger cluster tiers include higher IOPS thresholds.

    Note

    Cluster tiers M140 and larger are deployed with at least 1 TB of storage capacity by default. Clusters with 1 TB or more of storage capacity do not deplete burst credit balances.

Monitor Your Progress

These are a few possible methods to observe high disk I/O:

  • The disk IOPS use from the Disk IOPS graph in the cluster metrics exceeds the provisioned IOPS from the Atlas cluster configuration page.

  • The Normalized System CPU metric has a high IOWait curve. IOWait measures the percentage of time the CPU is idle and waiting for an I/O operation to complete. The Normalized System CPU chart is located under the Hardware Metrics section of the Metrics tab.

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