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title Monitoring data reference for Azure Functions
description This article contains important reference material you need when you monitor Azure Functions.
ms.date 10/27/2025
ms.custom
horz-monitor
build-2024
build-2025
ms.topic reference
ms.service azure-functions

Azure Functions monitoring data reference

[!INCLUDE horz-monitor-ref-intro]

See Monitor Azure Functions for details on the data you can collect for Azure Functions and how to use it.

See Monitor executions in Azure Functions for details on using Application Insights to collect and analyze log data from individual functions in your function app.

[!INCLUDE horz-monitor-ref-metrics-intro]

Hosting plans that allow your apps to scale dynamically support extra Functions-specific metrics:

Flex Consumption plan

These metrics are used to estimate the costs associated with on demand and always ready meters used for billing in a Flex Consumption plan:

[!INCLUDE functions-flex-consumption-metrics-table]

In this table, all execution units are calculated by multiplying the fixed instance memory size, such as 512 MB or 2,048 MB, by total execution times, in milliseconds.

These metrics are used to monitor the performance and scaling behavior of your function app in a Flex Consumption plan:

Metric Description
Automatic Scaling Instance Count The number of instances on which this app is running. Note that this is emitted every 30 seconds, and given Flex Consumption scales out and in fast, the number will be an aggregate of all new instances the app used in this time period. Make sure to change the aggregation to the minimum possible in the graph and the aggregation to "count".
Memory working set The current amount of memory used by the app, in MB. Can be further filtered for each instance of the app.
Average memory working set The average amount of memory used by the app, in megabytes (MB). Can be further filtered for each instance of the app.
CPU Percentage The average percentage of CPU being used. Can be further filtered for each instance of the app. This is currently rolling out and might not be available for apps in all regions yet.

These performance metrics help you understand resource utilization and scaling patterns in your Flex Consumption function app. The instance count metric is particularly useful for monitoring the dynamic scaling behavior, while memory and CPU metrics provide insights into resource consumption patterns.

Consumption plan

These metrics are used specifically when estimating Consumption plan costs.

[!INCLUDE functions-consumption-metrics-table]

Supported metrics for Microsoft.Web/sites

The following table lists the metrics available for the Microsoft.Web/sites resource type. Most of these metrics apply to both function app and web apps, which both run on App Service.

Note

These metrics aren't available when your function app runs on Linux in a Consumption plan.

[!INCLUDE horz-monitor-ref-metrics-tableheader] [!INCLUDE Microsoft.Web/sites]

[!INCLUDE horz-monitor-ref-metrics-dimensions-intro]

[!INCLUDE horz-monitor-ref-no-metrics-dimensions]

[!INCLUDE horz-monitor-ref-resource-logs]

Supported resource logs for Microsoft.Web/sites

[!INCLUDE Microsoft.Web/sites]

The log specific to Azure Functions is FunctionAppLogs.

For more information, see the App Service monitoring data reference.

[!INCLUDE horz-monitor-ref-logs-tables]

App Services

Microsoft.Web/sites

[!INCLUDE horz-monitor-ref-activity-log]

The following table lists operations related to Azure Functions that might be created in the activity log.

Operation Description
Microsoft.web/sites/functions/listkeys/action Return the keys for the function.
Microsoft.Web/sites/host/listkeys/action Return the host keys for the function app.
Microsoft.Web/sites/host/sync/action Sync triggers operation.
Microsoft.Web/sites/start/action Function app started.
Microsoft.Web/sites/stop/action Function app stopped.
Microsoft.Web/sites/write Change a function app setting, such as runtime version or enable remote debugging.

You may also find logged operations that relate to the underlying App Service behaviors. For a more complete list, see Microsoft.Web resource provider operations.

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