Step by step guidance in monitoring Application Gateway performance

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Step by step guidance in monitoring Application Gateway performance

Handinata Tanudjaja 360

Hi everyone,

Our company would like to be able to monitor and evaluate our Application Gateway's performance. The goal is to be able to identify any issue that hindering the performance and to be able to make necessary configuration to achieve the best performance.

Could we please have step by step guidance to achieve this? For example, what metrics we should look at and compare, how we should interpret the metrics, what configurations needed to change and/or added based on the metrics, etc.

Thank you

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Praveen Bandaru 3,145 Microsoft External Staff Moderator

Hello Handinata Tanudjaja

I understand that you are looking to monitor the application gateway performance.

You can check the application gateway logs and metrics to assess performance. Key metrics include response time, throughput, error rates, and latency, which can help identify issues.

Use Azure Monitor or Application Insights to collect and visualize these metrics. Ensure alerts are set for critical thresholds and regularly review the data to spot patterns or spikes in error rates or response times that may indicate performance problems.

Check the public document: Metrics for Application Gateway

Application Gateway provides several built‑in timing metrics related to the request and response, which are all measured in milliseconds.

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You can also configure a health probe to check if the application gateway backend is healthy or unhealthy. If your backend is unhealthy, you will receive an alert in the health probe logs. Check the below reference documents

Application Gateway health probes

Application Gateway - Backend health

Additionally, you can configure diagnostic logs to verify if requests are reaching the backend and to check the server status, including the response time of both the backend and the application gateway.

Check the reference documents:

Diagnostic logs for Application Gateway

AGWPerformanceLogs

If you have any other questions or are still running into more issues, let me know in the comments and I would be happy to help you.

Please do not forget to "Accept the answer” and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

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If you have any other questions or are still running into more issues, let me know in the "comments" and I would be happy to help you.

Handinata Tanudjaja 360 Reputation points

2025-05-07T01:28:48.3066667+00:00

Thank you.
Let's take an example so you could help me to set it up.
One thing I was asked about this metric was what was the percentage CPU and RAM were during "Backend last byte response time."

How do I set this up?

Praveen Bandaru 3,145 Microsoft External Staff Moderator

Hello Handinata Tanudjaja

Backend last byte response time approximates the sum of backend first byte response time and data transfer time. This number varies based on the size of requested objects and server network latency.

Backend connect time includes network latency and the backend server's TCP stack time to establish new connections. For TLS, it also includes handshake time.

Check the reference document for more understanding: https://learn.microsoft.com/en-us/azure/application-gateway/monitor-application-gateway-reference#supported-metrics-for-microsoftnetworkapplicationgateways

Check the public document for Backend metrics for Application Gateway

Compute unit measures the compute utilization of your Application Gateway.

Alert type	Condition	Description
Metric	Compute Unit utilization crosses 75% of average usage	Compute unit is the measure of compute utilization of your Application Gateway. Check your average compute unit usage in the last one month and set alert if it crosses 75% of it.
Metric	Capacity Unit utilization crosses 75% of peak usage	Capacity units represent overall gateway utilization in terms of throughput, compute, and connection count. Check your maximum capacity unit usage in the last one month and set alert if it crosses 75% of it.

Check the reference document: https://docs.azure.cn/en-us/application-gateway/monitor-application-gateway#application-gateway-alert-rules

Please do not forget to "Accept the answer” and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

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If you have any other questions or are still running into more issues, let me know in the "comments" and I would be happy to help you.

Praveen Bandaru 3,145 Reputation points Microsoft External Staff Moderator

2025-05-08T13:54:47.07+00:00

Hello Handinata Tanudjaja

Following up to see if the above answer was helpful. If this answers your query, do click Accept Answer and Yes for was this answer helpful. And, if you have any further query do let us know.

Please do not forget to "Accept the answer” and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

If you have any other questions or are still running into more issues, let me know in the "comments" and I would be happy to help you.
Handinata Tanudjaja 360 Reputation points

2025-05-08T19:44:46.9066667+00:00

Hi Praveen,
Thanks for the response.
It wasn't what I am looking for in regards to my question on how do I relate "Backend last byte response time" with the percentage CPU and RAM.
After my investigation, I was able to select the VM that corresponds to "Backend last byte response time" in the metric view.

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Step by step guidance in monitoring Application Gateway performance

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