Space on VM

Hello Justine,

To check how much storage space is being used on your Azure VM, you can check it directly from the VM or use Azure Monitor if you want to keep track of disk usage regularly.

If this is a Windows VM, you can check the available and used space by connecting to the VM through RDP and opening: File Explorer → This PC

You will see all the drives with the total size, used space, and free space available.

You can also check it using PowerShell: Get-PSDrive -PSProvider FileSystem

This will show the disk usage details for the VM drives.

For a Linux VM, connect to the VM using SSH and run: df -h

This will show the disk capacity, used space, and available free space.

If you are looking for continuous monitoring or want to get alerts when the disk space is running low, Azure Monitor for Virtual Machines can help with this.

You can use the below KQL query in Azure Monitor → Logs to check free disk space:

InsightsMetrics
| where Computer in ("DC10.na.contosohotels.com") // Windows
| where Namespace == "LogicalDisk"
| where Name == "FreeSpacePercentage"
| extend Disk=tostring(todynamic(Tags)["vm.azm.ms/mountId"])
| summarize arg_max(TimeGenerated, *) by Disk, Computer
| project TimeGenerated, Disk, Computer, Val
| where Val > 90

Please replace Your_VM_Name with your VM name. This will return the latest free space percentage for the disks monitored by Azure Monitor.

If you want to configure alerts:

Open Azure Portal → Virtual Machines

Select your VM

Go to Monitoring → Alerts

Create a new alert rule

Select the disk usage metric

Configure the threshold (for example, alert when disk usage reaches 90%)

Add an Action Group to receive notifications

This way, you don't need to manually check the disk space every time. Azure will notify you when the disk is close to running out of space.

You can refer to the below Microsoft documentation for more details:

Azure Monitor VM Insights overview: Azure Monitor VM Insights documentation

Expand Azure VM managed disk when more storage is required: Expand Azure managed disk documentation

Reference thread: https://learn.microsoft.com/en-us/answers/questions/2263855/disk-c-is-full-on-an-azure-vm

Welcome to Microsoft Q&A

Hello @Justine Yamane I hope you are doing well,

Method 1: Operating System Level (Direct)

The fastest and most accurate way to check disk space is to log directly into the Virtual Machine, as the guest OS manages the file system natively.

For Windows VMs: Connect via RDP or Bastion. Open File Explorer and click on This PC to view the capacity and used space of your C:\ drive and any attached data disks.

For Linux VMs: Connect via SSH or Bastion. Execute the command df -h in the terminal to view human-readable disk space usage across all mounted file systems.

Method 2: Azure Monitor & VM Insights (At Scale)

If you want to view disk space from the Azure Portal without logging into the VM, you must enable Guest-level monitoring.

Navigate to your Virtual Machine in the Azure Portal.

Scroll down the left menu to the Monitoring section and select Insights.

If not already configured, click Enable to install the Azure Monitor Agent (AMA).

Once data is flowing, click the Performance tab within VM Insights.

1. In the metric dropdown, select Logical Disk Space Used %. This will display the exact volume utilization from the perspective of the guest OS.

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