OneAgent site extension installation on Azure App service is slowing down application performance

[AnupamDey]

Hi Community,
After installing Dynatrace OneAgent site extension on Azure App services users are reporting application slowness issue.
As per the analysis, 20-30% spike has been observed on below App service parameters across all App services post OneAgent site extension installation.

• Threadcount
• Handle count
• File Sytem usage
• I/O other operations
• I/O sec Bytes
• I/O Sec operations per second

This is resulting in application slowness even on lower environments as well.
Dev environment: App service Plan is on PremiumV3 (P2v3) with 2 instance count
Test environment: App service Plan is on PremiumV2 (P2v2) with 3 instance count
Production environment: App service Plan is on PremiumV2 (P3v2) with 9 instance count

Open forum questions:

Has anyone faced similar kind of issue?
Is there any known issue with OneAgent site extensions on Azure App service?
What should be the idle/recommended App service Plan family size to install OneAgent site extensions?
Increasing the App service plan instance count will help or need to upgrade the App service plan family size?

[radek_jasinski]

Hi @AnupamDey 

When you install OneAgent (including on AKS) then all sorts of slowdowns can occur. However, the causes can be many.

• Have you verified the operation of Dynatrace on TST before? Were there any errors?
• Did you check the OA and AG logs for error messages?
• Do you have errors in the application logs?
• Are you using the RUM module to monitor the user?

Radek

[AnupamDey]

There were no errors found.
On Test environment as well application slows down when OneAgent site extension is installed.
Nothing suspicious found in OA and AG logs
No errors found on Application logs related to Dynatrace OA site extension
load Spike on App service and application slowness occurs even when RUM is disabled.

[g_kat]

Hi @AnupamDey 

Are you using Application Insights in parallel with Dynatrace? There could be some conflicts caused by both of them instrumenting the application.

Also, taking a memory dump or .NET profiler trace from Azure Diagnostic Tools could help you identify the culprit.

George

[AnupamDey]

Hi George,

Application Insight has been disabled prior to OA site extension installation, as we know both in parallel will conflict.