Some friends here on the Hyper-V team shared a PowerShell 2.0 script for merging VHDs:
# Merge VHDs param( [string]$mergePath = $(throw "Must specify full path for merging VHD"), [string]$parentPath = $(throw "Must specify full path of parent VHD") ) #obtain the Msvm_ImageManagementService class $ImageMgtService = get-wmiobject -class "Msvm_ImageManagementService" -namespace "root\virtualization" # Create the fixed VHD $result = $ImageMgtService.MergeVirtualHardDisk($mergePath,$parentPath) if($result.ReturnValue -eq 4096){ # A Job was started, and can be tracked using its Msvm_Job instance $job = [wmi]$result.Job # Wait for job to finish while($job.jobstate -lt 7){$job.get()} # Return the Job's error code return $job.ErrorCode } # Otherwise, the method completed return $result.ReturnValue
# Merge VHDs
param( [string]$mergePath = $(throw "Must specify full path for merging VHD"), [string]$parentPath = $(throw "Must specify full path of parent VHD") )
#obtain the Msvm_ImageManagementService class $ImageMgtService = get-wmiobject -class "Msvm_ImageManagementService" -namespace "root\virtualization"
# Create the fixed VHD $result = $ImageMgtService.MergeVirtualHardDisk($mergePath,$parentPath)
if($result.ReturnValue -eq 4096){ # A Job was started, and can be tracked using its Msvm_Job instance $job = [wmi]$result.Job # Wait for job to finish while($job.jobstate -lt 7){$job.get()} # Return the Job's error code return $job.ErrorCode } # Otherwise, the method completed return $result.ReturnValue
For more info on how to use PS cmdlets see: http://www.microsoft.com/technet/scriptcenter/topics/msh/cmdlets/index.mspx
See also James O’Neil’s New and improved PowerShell Library for Hyper-V. Now with more functions and... documentation!
For all 35 sample Hyper-V PS1 scripts in a zipfile, go to: Hyper-V PowerShell Example Scripts.zip-download