Resizes all partitions on a disk to the maximum size available on the disk. Windows OS.

Expand-AllVolumesToMaxSize.ps1

<#
.SYNOPSIS
    Resizes all partitions on a disk to the maximum size available on the disk.
.DESCRIPTION
    This script will resize all partitions on a disk to the maximum size available on the disk.
    This is useful when you have a disk that has been expanded in the hypervisor and you want to
    expand the partitions to use the new space. The script supports use of -WhatIf.
.NOTES
    Author: Robert D. Biddle
.LINK
    
.EXAMPLE
    Expand-AllVolumesToMaxSize.ps1
    This will expand all partitions on the local computer to the maximum size available on the disk.
.EXAMPLE
    Expand-AllVolumesToMaxSize.ps1 -ComputerName Server1
    This will expand all partitions on Server1 to the maximum size available on the disk.
.EXAMPLE
    Expand-AllVolumesToMaxSize.ps1 -ComputerName Server1,Server2
    This will expand all partitions on Server1 and Server2 to the maximum size available on the disk.
.EXAMPLE
    Get-Content .\Servers.txt | Expand-AllVolumesToMaxSize.ps1
    This will expand all partitions on the servers listed in Servers.txt to the maximum size available on the disk.
.EXAMPLE
    Get-Content .\Servers.txt | Expand-AllVolumesToMaxSize.ps1 -WhatIf
    This will show what would happen if you ran the command in the previous example.
#>

[CmdletBinding(SupportsShouldProcess)]
param (
    [Parameter(ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true)]
    [Alias('CN', 'Computer', 'Server', 'Servers')]
    [string[]]$ComputerName = @($env:COMPUTERNAME)
)

begin {
    $ErrorActionPreference = 'Stop'
}

process {
    foreach ($computer in $ComputerName) {
        try {
            $volumes = Get-Volume -CimSession $computer -ErrorAction Stop | Where-Object { $_.DriveLetter -ne $null }
            foreach ($volume in $volumes) {
                Write-Output "Checking Volume: $($volume.DriveLetter) on Computer: $computer"
                $partition = Get-Partition -CimSession $computer -Volume $volume -ErrorAction Stop
                if ($null -ne $partition) {
                    Write-Output "Checking Partition: $($partition.DiskNumber) on Volume: $($volume.DriveLetter) on Computer: $computer"
                    Update-Disk -CimSession $computer -Number $partition.DiskNumber
                    $diskSize = Get-PartitionSupportedSize -CimSession $computer -DiskNumber $partition.DiskNumber -PartitionNumber $partition.PartitionNumber
                    Write-Output "Disk Size: $($diskSize.SizeMax) Partition Size: $($partition.Size)"
                    if ($diskSize.SizeMax -gt $partition.Size) {
                        if ($PSCmdlet.ShouldProcess) {
                            Write-Output "Resizing Drive $($volume.DriveLetter): $($partition.DiskNumber) from: $($partition.Size) to: $($diskSize.SizeMax)"
                            Resize-Partition -CimSession $computer -DiskNumber $partition.DiskNumber -PartitionNumber $partition.PartitionNumber -Size $diskSize.SizeMax -Confirm:$false
                            Update-Disk -CimSession $computer -Number $partition.DiskNumber
                        }
                        else {
                            Write-Output "Resizing Drive $($volume.DriveLetter): $($partition.DiskNumber) from: $($partition.Size) to: $($diskSize.SizeMax)"
                            Resize-Partition -CimSession $computer -DiskNumber $partition.DiskNumber -PartitionNumber $partition.PartitionNumber -Size $diskSize.SizeMax -Confirm:$false
                            Update-Disk -CimSession $computer -Number $partition.DiskNumber
                        }
                    }
                    else {
                        Write-Output "Drive $($volume.DriveLetter): $($partition.DiskNumber) already at max size of $($diskSize.SizeMax)"
                    }
                }
            }
        }
        catch {
            Write-Error $Error[0]
        }
    }
}
    
end {
    $ErrorActionPreference = 'Continue'
}