I have recently moved a Drupal 7 site over to Azure on a Windows app service running PHP. I am also using Azure's MySQL database instance.
Since moving over to Azure, I noticed that the site is laggy when you are logged into the Drupal dashboard. Pages can take around 6-8 seconds to load when just clicking around the various dashboard areas. The site when not logged into Drupal works absolutely fine, so somewhere along the line there is something in Drupal Admin causing the slow down.
The app service is on a P1V2 tier, which is more than what the Drupal application requires and judging by the usage stats, it's not exceeding any resources.
Is there anything I am missing specifically to cause this slow down? I have removed any unneeded plugins and disabled the update module.
After much investigation, I found the workaround was to downgrade the PHP framework version from 7.2 to 7.1 even though the version of Drupal I was using is compatible with 7.2. After making this change from within the Azure configuration screen, the dashboard load time reduced considerably.