/Get-ScratchSpace Retrieves the configured amount of Windows PE system volume scratch space. This setting represents the ...

/Get-ScratchSpace

  Retrieves the configured amount of Windows PE system volume scratch space.
  This setting represents the amount of writeable space available on the
  Windows PE system volume when booted in ramdisk mode.

  Example:
    DISM.exe /Image:C:	est\offline /Get-ScratchSpace