Azure App Service Plan 'out of space' yet portal shows 99% free space

Question

When I deploy a project via Devops release pipeline I'm receiving the following error when running App Service Deploy:

There is not enough space on the disk.

I am confused how this can be the case given that the App Service Plan which the relevant app service resides has a 50Gb storage limit, and only just over 1.1Gb of that is being used.

Here's the full debug output from the devops pipeline:

2022-11-16T10:32:16.4226641Z ##[debug]ZIP Deploy response: {"statusCode":500,"statusMessage":"Internal Server Error","headers":{"content-length":"8414","connection":"close","content-type":"application/json; charset=utf-8","date":"Wed, 16 Nov 2022 10:32:16 GMT","server":"Microsoft-IIS/10.0","cache-control":"no-cache","expires":"-1","pragma":"no-cache","x-ms-request-id":"ef65e217-ab18-4421-9edc-7ae664b7fbba","x-aspnet-version":"4.0.30319","x-powered-by":"ASP.NET"},"body":{"Message":"An error has occurred.","ExceptionMessage":"There is not enough space on the disk.\r\n","ExceptionType":"System.IO.IOException"}  

I've checked the storage account via SCM and can see that most of the storage is taken up with previously deployed Zip files, however this should not be an issue given that there is still 48+Gb space.

Is this a configuration issue? Can I manually increase/recalculate the available storage for the plan without changing tier? Any advice gratefully received.

Answer 1

@Rory McCrossan Thank you for reaching out to Microsoft Q&A. Apologize for the inconvenience caused on this.

Based on the shared information, we have understood that you are trying to deploy your app through Azure deVops and it is failed with error "There is not enough space on the disk" and also we see that(from shared screenshot) you have multiple app running under the same app service plan.

This might be happened due to the insufficient space in temp files not in the file system storage. App service file system comes with persisted files and temporary files.

• Persisted files: This is what you can view as your web site's files. They follow a structure described here. They are rooted in %HOME% directory. For App Service on Linux and Web app for Containers, persistent storage is rooted in /home.
  All the files in persistent storage will remain even after the app restarts as well and these files are shared between all instances of your site (when you scale it up to multiple instances).
• Temporary files: Unlike Persisted files, these files are not shared among site instances. Also, you cannot rely on them staying there. For instance, if you restart a web app, you'll find that all of these folders get reset to their original state.

You refer to this documentation for more information about the persistent files and temporary files in app service file system.

1. If you web app is running on the Windows app service plan i would suggest you install the Azure Web Apps Disk Usage extensions from site extensions through kudu and using that extension you understand which app is consuming more space and you can delete the unwanted space accordingly. Refer to this blog post to understand more what is taking my disk space for my azure web apps.
2. If you webapp are running on the Linux app service plan I would suggest restarting all the apps inside the app service plan to clear that temp file or try to scaleup the app service plan to next tier to increase the temp size.

Feel free to reach back to me if you have any further questions on this.