Set-HyperVVMVHDSize

Hyper-V: Resizes a virtual machine virtual hard disk

Script

#Requires -Version 5.1
#Requires -Modules Hyper-V

[CmdletBinding()]
Param (
    [string]$ComputerName = "localhost",

    [PSCredential]$Credential,

    [Parameter(Mandatory = $true)]
    [string]$Name,

    [Parameter(Mandatory = $true)]
    [ValidateSet('SCSI', 'IDE')]
    [string]$ControllerType,

    [int]$ControllerNumber = 0,

    [int]$ControllerLocation = 0,

    [uint64]$SizeBytes,

    [switch]$ToMinimumSize
)

Process {
    try {
        $params = @{
            'ComputerName' = $ComputerName
            'ErrorAction'  = 'Stop'
        }
        if ($Credential) { $params.Add('Credential', $Credential) }

        $vm = Get-VM @params | Where-Object { $_.Name -eq $Name -or $_.Id -eq $Name }

        if (-not $vm) {
            throw "Virtual machine '$Name' not found on '$ComputerName'."
        }

        $drive = Get-VMHardDiskDrive -VM $vm | Where-Object { 
            $_.ControllerType -eq $ControllerType -and 
            $_.ControllerNumber -eq $ControllerNumber -and 
            $_.ControllerLocation -eq $ControllerLocation 
        }

        if (-not $drive) {
            throw "No hard disk drive found on $ControllerType controller $ControllerNumber at location $ControllerLocation for VM '$Name'."
        }

        $resizeParams = @{ 'Path' = $drive.Path; 'ErrorAction' = 'Stop' }
        if ($Credential) { $resizeParams.Add('Credential', $Credential) }
        else { $resizeParams.Add('ComputerName', $ComputerName) }

        if ($ToMinimumSize) {
            Resize-VHD @resizeParams -ToMinimumSize
        }
        elseif ($SizeBytes) {
            Resize-VHD @resizeParams -SizeBytes $SizeBytes
        }
        else {
            throw "Either -SizeBytes or -ToMinimumSize must be specified."
        }

        $updatedVHD = Get-VHD @resizeParams
        
        $result = [PSCustomObject]@{
            VMName             = $vm.Name
            VHDPath            = $drive.Path
            ControllerType     = $ControllerType
            ControllerNumber   = $ControllerNumber
            ControllerLocation = $ControllerLocation
            NewSize            = $updatedVHD.Size
            MinimumSize        = $updatedVHD.MinimumSize
            Action             = "VHDResized"
            Status             = "Success"
            Timestamp          = Get-Date -Format "yyyy-MM-dd HH:mm:ss"
        }

        Write-Output $result
    }
    catch {
        throw
    }
}

Customize

ComputerName string

Specifies the name of the Hyper-V host. Defaults to the local machine.

Credential PSCredential

Specifies the credentials to use for the remote connection.

Name string

Specifies the name or ID of the virtual machine.

ControllerType string

Specifies the controller type (SCSI or IDE).

ControllerNumber int

Specifies the controller number.

ControllerLocation int

Specifies the location on the controller.

SizeBytes uint64

Optional. Specifies the new size in bytes (e.g., 100GB, 1TB).

ToMinimumSize switch

Off

Optional. If set, resizes the disk to its minimum possible size.