D:\Local storage at limits

Question

D:\Local storage at limits

Dan Latvala 1

My .NET web app started throwing random and intermittent 500 errors on Friday. In looking at the logs, it appears that the site will generate random IOException errors that say, "there is not enough space on the disk." This happens on multiple pages in the application and at random times.

When looking at Kudu, the D:\Local drive fluctuates between having 0 Mb and 100 Mb free. I have four small apps running on the app service plan, and I am using about 5% of my quote for the service plan.

I've tried restarting all the applications to clear out the temp files, but still the D:\local drive does not shrink.

Thanks in advance for any insights.

Dan

Lan Tran Ngoc 1 Reputation point

2022-11-30T10:46:05.467+00:00

@VenkateshDodda-MSFT
I have the same issue with @Dan Latvala .
My webapp is also running on Windows App Service.
I checked Kudo environment.

D:\home usage: 51,200 MB total; 50,081 MB free
D:\local usage: 11,264 MB total; 2 MB free

I restarted the webapp many times. The D:\local free space go up to 800MB at first, the gradually when back to 2MB.
I don't know which file is taking up space. I used below ps script, and the local folder usage is only 80MB.

Get-ChildItem D:\local -recurse | Measure-Object -property length -sum
VenkateshDodda-MSFT 25,111 Reputation points Microsoft Employee Moderator

2022-11-30T11:02:50.207+00:00

@Lan Tran Ngoc Could you try scaling out the app service plan to next tier and check whether it works out. If not i would recommend you create a new Q&A thread from here.
Dan Latvala 6 Reputation points

2022-11-30T17:50:00.747+00:00

Here's what fixed it for me. I scaled from a B1 instance up to a B2. This changed my local drive size to 15 Mb, and it was nearly all free space. Then I scaled back down to B1, and now I am only using about 500 Mb of the allotted 11 GB.

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Lan Tran Ngoc 1 Reputation point

2022-11-30T10:46:05.467+00:00

@VenkateshDodda-MSFT
I have the same issue with @Dan Latvala .
My webapp is also running on Windows App Service.
I checked Kudo environment.

D:\home usage: 51,200 MB total; 50,081 MB free
D:\local usage: 11,264 MB total; 2 MB free

I restarted the webapp many times. The D:\local free space go up to 800MB at first, the gradually when back to 2MB.
I don't know which file is taking up space. I used below ps script, and the local folder usage is only 80MB.

Get-ChildItem D:\local -recurse | Measure-Object -property length -sum
VenkateshDodda-MSFT 25,111 Reputation points Microsoft Employee Moderator

2022-11-30T11:02:50.207+00:00

@Lan Tran Ngoc Could you try scaling out the app service plan to next tier and check whether it works out. If not i would recommend you create a new Q&A thread from here.
Dan Latvala 6 Reputation points

2022-11-30T17:50:00.747+00:00

Here's what fixed it for me. I scaled from a B1 instance up to a B2. This changed my local drive size to 15 Mb, and it was nearly all free space. Then I scaled back down to B1, and now I am only using about 500 Mb of the allotted 11 GB.

Answer 1

VenkateshDodda-MSFT 25,111 Microsoft Employee Moderator

@Dan Latvala Thanks for reaching out to Microsoft Q&A. Apologize for the inconvenience caused on this.

Is your .NET webapp running on Windows App Service plan or Linux App Service plan?

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.
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.

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

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

Dan Latvala 1 Reputation point

2022-11-23T13:32:31.697+00:00

Hello,

Thanks for the response. I am using a Windows app service plan. I have installed the extension that you mentioned, however it only appears to let me view the space that is consumed on the D:\Home drive. My issue is with the D:\Local drive. Is there a way I can look at the space on that drive? From the reading I have done, that appears to be mostly temporary file storage. Restarting the four apps on that service plan has not reduced the size.

Dan
Dan Latvala 1 Reputation point

2022-11-23T14:08:49.61+00:00

I have also noticed as I am monitoring the size of the environment from Kudu that it will drop by 2-3 Gb very briefly and then within 30 seconds become full again.

Is it possible there is an issue with the app service plan VM?
Dan Latvala 1 Reputation point

2022-11-23T19:06:09.21+00:00

Update for @VenkateshDodda-MSFT - I think I have narrowed down the large folders to D:\Local\AppData and D:\Local\IIS Temporary Compressed Files. Neither folder allows me to see the specific files that are using up the space, but I was able to use a Powershell script to determine the size of the other files in D:\Local, and all of them combined are less than 500 Mb. The remaining 10.5 Gb must be in these two folders.
VenkateshDodda-MSFT 25,111 Reputation points Microsoft Employee Moderator

2022-11-24T09:49:32.86+00:00
@Dan Latvala Thanks for sharing more information. Below are the ways to delete those temporary files.

You can delete those temporary files form KUDU console select Debug explorer --> Click on system drive --> go to specific folder and either \home or \local under the click on delete.

Try scaling up and scaling down the app service plan to clean those temporary files.

By default all the temporary file will get deleted within 24 hours or 48 hours.

Looks like your application is writing the data to D:\local drive it is always recommended to write to storage account refer to this documentation on how to mount azure storage account for app service.
Dan Latvala 6 Reputation points

2022-11-27T19:24:06.897+00:00

Thank you, @VenkateshDodda-MSFT . I still could not find the large files with the system drive explorer. I scaled the app up and the drive was reset immediately. I am still not sure why the files temp files were not shrinking like they should have. I will check out the mounting of a storage account; I was not aware I was using the D:\local drive.
VenkateshDodda-MSFT 25,111 Reputation points Microsoft Employee Moderator

2022-11-28T10:24:53.44+00:00

@Dan Latvala Thanks for your follow up questions on this. We have suggested that using system drive explorer method is the easiest way to clear out those files which you have mentioned in your earlier response that using some PowerShell script you are able to identify that expect the D:\Local\AppData and D:\Local\IIS Temporary Compressed Files folders occupied 10.5GB.

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D:\Local storage at limits

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