If you are playing with VDI and you are want to increase the rebuild time and not want to set the registry key. You can change this by PowerShell
get-command get-rd*
Get-RDVirtualDesktopConcurrency
FQDN Concurrency
—- ———–
HYPERV1202.MVP.LOCAL 1
set-RDVirtualDesktopConcurrency -ConcurrencyFactor 20
WoooW 20 VM’s rebuilding at the same time ! Remember this will take a lot of IOPS How Much ? read my other post on Resource metering