This article provides guidance on troubleshooting common issues with Azure Files. Azure Files offers fully managed cloud file shares that are accessible via the industry-standard Server Message Block (SMB) protocol and the Network File System (NFS) protocol.

Common Issues and Solutions

Connectivity Issues

If you are unable to connect to your Azure File share, consider the following:

  • Firewall or Network Security Groups (NSGs): Ensure that port 445 (for SMB) or port 2049 (for NFS) is open on your firewall and any NSGs associated with your storage account or virtual network.
  • Private Endpoint: If using a private endpoint, verify that your DNS resolution is correctly configured to point to the private IP address.
  • On-premises Connectivity: For on-premises access, ensure your network routing and VPN/ExpressRoute connections are stable.

Performance Issues

Slow performance can be due to various factors. Here are some common causes and troubleshooting steps:

  • Share and File Size: Larger shares and individual files can impact performance. Consider the ingress/egress limits for your chosen service tier.
  • Throttling: Azure Files may throttle requests if you exceed the limits for transactions or ingress/egress bandwidth. Monitor your storage account metrics for throttling events.
  • Client-Side Issues: Network latency between the client and Azure, or insufficient client resources (CPU, memory, disk IOPS), can also contribute to perceived slowness.
  • SMB Version: Ensure clients are using SMB 3.0 or later for optimal performance.

Authentication and Authorization

Problems with accessing files may stem from incorrect authentication:

  • Storage Account Key: If accessing with a storage account key, ensure the key is correct and has not expired or been regenerated.
  • Azure AD DS / AD DS: When using identity-based authentication (Azure AD Domain Services or on-premises Active Directory Domain Services), verify that your identity provider is properly configured, domain controllers are reachable, and user/group permissions are set correctly on the share and NTFS level.
  • SAS Tokens: If using Shared Access Signature (SAS) tokens, ensure they are valid, have the correct permissions, and the expiry time has not passed.

Data Access Errors

You might encounter errors when trying to read, write, or delete files:

  • Permissions: Double-check the permissions configured at both the Azure File share level (RBAC for Azure AD access) and the file/folder level (NTFS permissions for AD DS/Azure AD DS).
  • File Locks: An existing file lock on a file can prevent other operations. This is more common with certain applications.
  • Corrupted Data: In rare cases, data corruption might occur. Consider using Azure's data integrity features or performing backups.

Important Note

Always consult the official Azure documentation for the most up-to-date information and specific error codes.

Monitoring and Diagnostics

Azure provides several tools to help diagnose issues:

  • Azure Monitor: Collects and analyzes telemetry from your Azure resources. Use it to track metrics like transactions, latency, and ingress/egress.
  • Storage Analytics Logs: Enable logging to capture detailed information about requests made to your storage account.
  • Azure Network Watcher: Provides tools for network monitoring, diagnostics, and visualization.

Specific Error Scenarios

Error Code: -2147024891 (Access Denied)

This error typically indicates a permissions issue. Verify your credentials and the access control lists (ACLs) for the share and individual files/folders.

Error Code: ERROR_BAD_NET_NAME

This often points to an issue with the network path or share name. Ensure the share name is spelled correctly and that you can reach the storage account endpoint.

Warning

Incorrectly configuring network security can lead to unauthorized access. Always follow security best practices.

Further Resources