title: Azure Linux Web App Service - System.IO.IOException: Readonly File Error
body: <p>The web app already running on .NET Core 3.1 LTS with IIS (windows server 2019)</p>
  <p>Recently, I deployed as an Azure Web App Service but I encountered a file write error.</p>
  <p>The application trying to create a new file for some business requirement.</p>
  <p>Error message; <code>System.IO.IOException: Read-only file system</code></p>
  <p>Has anyone encountered this problem on Azure Linux Web App?</p>
  <p>Solved: The Azure Linux Web App Service doesn't support directly file uploading to a regular folder under the wwwRoot. If you can running on the linux web app service, you need to use blob / storage etc..</p>