Understanding Average Load metric in Confluence Cluster
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Purpose
This Knowledge article explains what the Load column in Confluence's Clustering page means and how it is calculated.
Summary
The Load column in the Clustering page is taken from the average load of your Operating System (OS). Hence, it is strongly recommended to check the actual representation of the Load in your OS.
The actual metric is calculated in Confluence using the com.atlassian.cluster.monitoring.supplier.RuntimeInformationSupplier.java class, particularly this way:
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final Double systemLoadAverage = operatingSystem.getSystemLoadAverage();
final String systemLoadAverageValue = systemLoadAverage >= 0 ? String.valueOf(systemLoadAverage) : i18n.getText(NOT_AVAILABLE_KEY);
final Integer availableProcessors = operatingSystem.getAvailableProcessors();
final String percentLoad = systemLoadAverage >= 0 ? percentFormat.format((systemLoadAverage / availableProcessors) * 100) + "%" : i18n.getText(NOT_AVAILABLE_KEY);
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...The average load for Linux depends on the number of CPUs and cores the system has. Generally, an average load lower than the number of CPU cores is normal, as it means there are enough resources for all processes to run smoothly. For example, if your system is running with 8 CPUs, the load could grow up to a value of 800%.
On one hand, a high average load with a low number of cores indicates an overwhelmed system. On the other hand, a low average load with a high number of cores means that the system has spare capacity and is able to manage more processes.
External Related Links
You can read about how the Load Average is measure in Linux in these external links:
- Red Hat Customer Portal > How is load average calculated
- Load average: What is it, and what's the best load average for your Linux servers?
- What Is Linux Average Load?