Testing boot Differential VHDs made from dynamical VHDs installed in Wimboot mode:
From previous Post we confirmed MinWin Differential VHDs made from fixed size VHDs installed in Wimboot mode, boot fine as Filedisk from internal HD on MBR/CSM or UEFI environments using Windows boot manager or grub4dos + ntloader.
I made in my internal HD, in the drive dedicated to hold my VHDs, a new installation of my already made MinWin.wim file, in Wimboot mode in a dynamical (expandable), single NTFS partition, 2 GB VHD, and named it as MinWin-WB-0.vhd. The resulting VHD has when mounted an internal used space of about 60 MB, when unmounted occupies less than 100 MB, but never booted from it, it was not fragmented internally, but as usually happends to all expandable VHDs, it was externally fragmented in the drive where it resides, after unmout it just defragmented the VHD file using Defraggler portable (located in my attached Y-Drive.vhd).
Using MinWin-WB-0.vhd as the Parent VHD, I created by command line a Differential VHD, named MinWin-WB-1.vhd, which by design is also a dynamical (expandable) VHD, having also when mounted an internal used space of about 60 MB, and also occupies less than 100 MB, when unmounted, before first boot.
After that I created for the MinWin-WB-1.vhd both BCDs entries, and both grub4dos menu.lst entries for MBR and UFI, and booted from it as Filedisk, as expected all worked flawlessly in all cases, not a single issue, of course after booting and using it for some time the internal used space increased to about 280 MB, having it mounted and running from it, when checked the fragmentation on the drive holding it, the MinWin-WB-1.vhd file (2 GB when online) was very fagmented externally, and decided to defragment the VHD file (not its content, that was fine), just to see if this could create some issue, having it online, used Defraggler portable again, the process finished very fine without any issue, and it rebooted later very fine again.
After switch off, I booted from a WinPE (for faster boot), to take a look to the drive holding it, the size of the MinWin-WB-1.vhd (now offline) was about 300 MB, all contiguous, and located now in a place of the drive where it can freely expand when mounted to its 2 GB full size without getting fragmented again, as long as I keep the precaution to have it attached when adding a new file to that drive.
Then I repeated the process againg, this time using MinWin-WB-1.vhd as Parent VHD and created MinWin-WB-2.vhd as its Child VHD, it booted very fine from MS bootmanager, but not from grub4dos + ntloader, so this shows grub4dos + ntloader only works fine for first level Differential VHDs.
Conclusions of this test:
1 - If Parent VHD is a dynamical VHD installed in Wimboot mode we can assign to it a bigger size, without impacting the combined size of the VHDs set since the beginning.
2 - The used size (Parent + Child) of a set of Differential VHDs made from dynamical VHDs installed in Wimboot mode, is smaller than if using as parent a fixed size VHD, and this allows to have more free space in the child VHD.
3 - The total used size (Parent + Child + WIM file) of a set of Differential VHDs made from dynamical VHDs installed in Wimboot mode, is smaller than if using as parent a fixed size VHD installed in Compact LZX mode (the more versatile in previous Post), and also allows to have more free space in the child VHD.
4 - First level Differential VHDs made from dynamical VHDs installed in Wimboot mode, boot fine as Filedisk from internal HD on MBR/CSM or UEFI environments, using Windows boot manager or grub4dos + ntloader, but not from a USB device if using grub4dos + ntloader.
5 - Second level Differential VHDs made from dynamical VHDs installed in Wimboot mode, boot fine as Filedisk from internal HD or USB device, using Windows boot manager, but DO NOT boot fine in both cases if using using grub4dos + ntloader.
Final conclusions, including the info in previous post I can say:
I- Windows boot manager is the best option to (MBR/CSM and UEFI) boot as Filedisk all kind of Differential VHDs, from internal HD or USB device.
II - Windows boot manager supports Filedisk booting multi level Differential VHDs.
III - Differential VHDs made from dynamical VHDs installed in Wimboot mode, are the best option for space saving.
alacran