Change the size of a virtual machine

Applies to: ✔️ Linux VMs ✔️ Windows VMs ✔️ Flexible scale sets

This article shows you how to move a VM to a different VM size.

After you create a virtual machine (VM), you can scale the VM up or down by changing the VM size. In some cases, you must deallocate the VM first. This can happen if the new size is not available on the hardware cluster that is currently hosting the VM.

If your VM uses Premium Storage, make sure that you choose an s version of the size to get Premium Storage support. For example, choose Standard_E4s_v3 instead of Standard_E4_v3.

Change the VM size

Portal

1. Open the Azure portal.
2. Open the page for the virtual machine.
3. In the left menu, select Size.
4. Pick a new size from the list of available sizes and then select Resize.

If the virtual machine is currently running, changing its size will cause it to be restarted.

If your VM is still running and you don't see the size you want in the list, stopping the virtual machine may reveal more sizes.

Warning

Deallocating the VM also releases any dynamic IP addresses assigned to the VM. The OS and data disks are not affected.

If you are resizing a production VM, consider using Azure Capacity Reservations to reserve Compute capacity in the region.

CLI

To resize a VM, you need the latest Azure CLI installed and logged in to an Azure account using az login.

1. View the list of available VM sizes on the hardware cluster where the VM is hosted with az vm list-vm-resize-options. The following example lists VM sizes for the VM named myVM in the resource group myResourceGroup region:

   az vm list-vm-resize-options \
   --resource-group myResourceGroup \
   --name myVM --output table
   

2. If the desired VM size is listed, resize the VM with az vm resize. The following example resizes the VM named myVM to the Standard_DS3_v2 size:

   az vm resize \
   --resource-group myResourceGroup \
   --name myVM \
   --size Standard_DS3_v2
   

   The VM restarts during this process. After the restart, your existing OS and data disks are remapped. Anything on the temporary disk is lost.

3. If the desired VM size is not listed, you need to first deallocate the VM with az vm deallocate. This process allows the VM to then be resized to any size available that the region supports and then started. The following steps deallocate, resize, and then start the VM named myVM in the resource group named myResourceGroup:

   # Variables will make this easier. Replace the values with your own.
   resourceGroup=myResourceGroup
   vm=myVM
   size=Standard_DS3_v2
   
   az vm deallocate \
   --resource-group $resourceGroup \
   --name myVM
   az vm resize \
   --resource-group $resourceGroup \
   --name $vm \
   --size $size
   az vm start \
   --resource-group $resourceGroup \
   --name $vm
   

   Warning

   Deallocating the VM also releases any dynamic IP addresses assigned to the VM. The OS and data disks are not affected.

   If you are resizing a production VM, consider using Azure Capacity Reservations to reserve Compute capacity in the region.

PowerShell

Use PowerShell to resize a VM not in an availability set.

Set some variables. Replace the values with your own information.

$resourceGroup = "myResourceGroup"
$vmName = "myVM"

List the VM sizes that are available in the region where the VM is hosted.

Get-AzVMSize -ResourceGroupName $resourceGroup -VMName $vmName 

If the size you want is listed, run the following commands to resize the VM. If the desired size is not listed, go on to step 3.

$vm = Get-AzVM -ResourceGroupName $resourceGroup -VMName $vmName
$vm.HardwareProfile.VmSize = "<newVMsize>"
Update-AzVM -VM $vm -ResourceGroupName $resourceGroup

If the size you want is not listed, run the following commands to deallocate the VM, resize it, and restart the VM. Replace <newVMsize> with the size you want.

Stop-AzVM -ResourceGroupName $resourceGroup -Name $vmName -Force
$vm = Get-AzVM -ResourceGroupName $resourceGroup -VMName $vmName
$vm.HardwareProfile.VmSize = "<newVMSize>"
Update-AzVM -VM $vm -ResourceGroupName $resourceGroup
Start-AzVM -ResourceGroupName $resourceGroup -Name $vmName

Warning

Deallocating the VM also releases any dynamic IP addresses assigned to the VM. The OS and data disks are not affected.

If you are resizing a production VM, consider using Azure Capacity Reservations to reserve Compute capacity in the region.

Use PowerShell to resize a VM in an availability set

If the new size for a VM in an availability set is not available on the hardware cluster currently hosting the VM, then all VMs in the availability set will need to be deallocated to resize the VM. You also might need to update the size of other VMs in the availability set after one VM has been resized. To resize a VM in an availability set, perform the following steps.

$resourceGroup = "myResourceGroup"
$vmName = "myVM"

List the VM sizes that are available on the hardware cluster where the VM is hosted.

Get-AzVMSize `
-ResourceGroupName $resourceGroup `
-VMName $vmName 

If the desired size is listed, run the following commands to resize the VM. If it is not listed, go to the next section.

$vm = Get-AzVM `
-ResourceGroupName $resourceGroup `
-VMName $vmName 
$vm.HardwareProfile.VmSize = "<newVmSize>"
Update-AzVM `
-VM $vm `
-ResourceGroupName $resourceGroup

If the size you want is not listed, continue with the following steps to deallocate all VMs in the availability set, resize VMs, and restart them.

Stop all VMs in the availability set.

$availabilitySetName = "<availabilitySetName>"
$as = Get-AzAvailabilitySet `
-ResourceGroupName $resourceGroup `
-Name $availabilitySetName
$virtualMachines = $as.VirtualMachinesReferences |  Get-AzResource | Get-AzVM
$virtualMachines |  Stop-AzVM -Force -NoWait  

Resize and restart the VMs in the availability set.

$availabilitySetName = "<availabilitySetName>"
$newSize = "<newVmSize>"
$as = Get-AzAvailabilitySet -ResourceGroupName $resourceGroup -Name $availabilitySetName
$virtualMachines = $as.VirtualMachinesReferences |  Get-AzResource | Get-AzVM
$virtualMachines | Foreach-Object { $_.HardwareProfile.VmSize = $newSize }
$virtualMachines | Update-AzVM
$virtualMachines | Start-AzVM

Next steps

For additional scalability, run multiple VM instances and scale out. For more information, see Automatically scale machines in a Virtual Machine Scale Set.