Why got exception "No such device : '/home/site/wwwroot'" from Azure Function

Question

I have an Azure Functions developed by NodeJS, it's a callback for Docusign which used for sending and receiving contracts signature, when there is a signature sent or received, the callback(the Azure Function) would be triggered, I set up an Application Insights for tracking its running and some possible exceptions. It is always working fine, but every few days, approximately a week, there was an exception occurred, saying "No such device : '/home/site/wwwroot'". This exception didn't cause any blocks to the function, the function and Docusign have re-try policy, one time failed, it will try again.

I just want to know what caused this, and how to resolve it. Here is more details about the exception.

|Message|No such device : '/home/site/wwwroot'|| | -------- | -------- | -------- | |Message|No such device : '/home/site/wwwroot'|| |Exception type|System.IO.IOException|| |Failed method|System.IO.Enumeration.FileSystemEnumerator1.FindNextEntry|| |Problem Id|System.IO.IOException at System.IO.Enumeration.FileSystemEnumerator1.FindNextEntry|| |Assembly|System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e|

Category	Host.Startup
Category	Host.Startup
ProcessId	27
EventName	ErrorOccurredDuringStartupOperation
EventId	515
LogLevel	Error
prop__{OriginalFormat}	A host error has occurred during startup operation '{operationId}'.
HostInstanceId	06c58091-ba13-4f47-8363-ef2fa8a122da
FormattedMessage	A host error has occurred during startup operation 'f67795f0-f626-46eb-a736-2728ab63a70c'.

Answer 1

Hello [@Catherine Xiao](/users/na/?userid=7c45f2ef-4f5b-48a3-a14e-95535559e737

Based on the provided information, it seems that the error is related to the file system of the Azure Function. The error message No such device : '/home/site/wwwroot indicates that the file system is not able to find the specified directory.

This error can occur due to various reasons such as file system corruption, permission issues, or disk space issues. To resolve this issue, you can try the following steps:

1. Restart the Azure Function: Sometimes, restarting the Azure Function can resolve the issue. You can restart the function from the Azure portal or by using the Azure CLI.
2. Check the disk space: Check if the disk space of the Azure Function is full. If the disk space is full, you can try to free up some space by deleting unnecessary files or increasing the disk space.
3. Check the file system permissions: Check if the file system permissions are set correctly. Make sure that the Azure Function has the necessary permissions to access the file system.
4. Check the file system for corruption: Check if the file system is corrupted. You can run a file system check to identify and fix any file system errors. If the issue persists, you can try to enable diagnostic logging for the Azure Function to get more information about the error. You can also contact Microsoft support for further assistance.

---

I hope that this response has addressed your query and helped you overcome your challenges. If so, please mark this response as Answered. This will not only acknowledge our efforts, but also assist other community members who may be looking for similar solutions.