Azure File Storage

Azure Files provides fully managed cloud file shares accessible over SMB (Windows) and NFS (Linux). Mount them on VMs, on-premises machines, or containers — works like a regular network drive.

Simple Explanation

Azure Files is like a USB drive in the cloud that many computers can plug into simultaneously. You mount it as a network drive (SMB) or filesystem path (NFS), and apps see it as a normal folder.

When to Use Azure Files

• Lift-and-shift of on-premises apps that use UNC file paths.
• Shared configuration files or application settings across multiple VMs.
• Persistent storage volume for containers (AKS, ACI persistent volumes).
• Cross-platform shared storage (Windows + Linux VMs sharing the same share).

Protocols

Commands

# Create a file share (5 GB quota)
az storage share create \
  --account-name mystorageacct \
  --name myfileshare \
  --quota 5

# Upload a file
az storage file upload \
  --account-name mystorageacct \
  --share-name myfileshare \
  --source ./config.yml \
  --path config.yml

# List files in share
az storage file list \
  --account-name mystorageacct \
  --share-name myfileshare \
  --output table

# Mount on Linux VM (SMB)
# Get storage account key first
ACCOUNT_KEY=$(az storage account keys list \
  --resource-group rg-storage \
  --account-name mystorageacct \
  --query "[0].value" --output tsv)

sudo mkdir /mnt/myfileshare
sudo mount -t cifs \
  //mystorageacct.file.core.windows.net/myfileshare \
  /mnt/myfileshare \
  -o vers=3.0,username=mystorageacct,password=$ACCOUNT_KEY,dir_mode=0777,file_mode=0777

# Make mount persistent (add to /etc/fstab)
echo "//mystorageacct.file.core.windows.net/myfileshare /mnt/myfileshare cifs vers=3.0,username=mystorageacct,password=$ACCOUNT_KEY,dir_mode=0777,file_mode=0777" >> /etc/fstab

Azure File Sync

Azure File Sync extends Azure Files to on-premises servers — synchronizing file shares bidirectionally. On-prem servers cache hot files locally; cold files are tiered to the cloud. Great for offices with slow WAN but needing cloud backup.

Hands-on

1. Create a file share with 5 GB quota in an existing storage account.
2. Upload a sample config file from CLI.
3. Mount the share on a Linux VM and verify you can read the file.
4. Edit the file from inside the VM and verify the change appears in Portal.
5. Explore the "Connect" button in Portal — it auto-generates the mount command for Windows/Linux/macOS.

Debugging Scenario

Issue: SMB mount fails with mount error(13): Permission denied.

• Verify the storage account key is correct and current.
• Check NSG outbound rules — SMB uses port 445, which many ISPs/enterprises block.
• If port 445 is blocked, use Azure File Sync or access via REST API instead.
• For enterprise environments, configure a private endpoint so SMB traffic stays on the VNet (no need for port 445 on public internet).

Interview Questions

Summary

Azure Files is the cloud equivalent of an on-premises file server — mountable over SMB or NFS, compatible with legacy apps, and shareable across multiple VMs and containers. For modern apps, prefer Blob Storage; for legacy or lift-and-shift, Azure Files is the right choice.