/Set-ScratchSpace:{32|64|128|256|512} Sets the configured amount of Windows PE system volume scratch space. This setting ...

/Set-ScratchSpace:{32|64|128|256|512}

  Sets 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:\test\offline /Set-ScratchSpace:512