Question Has anyone here set up software mirroring of an entire GPT boot drive on Windows Pro/Server?

[mikeymikec]

I've set up software mirroring a few times before on Windows Pro/Server editions but on Server 2022 Standard and 2x 4TB NVMe M.2 disks I'm encountering difficulties.

The procedure AFAIK should go like this:
https://learn.microsoft.com/en-us/t...nd-storage/mirror-system-boot-partition-raid1
TLDR: Go into Disk Management, make sure both disks are configured as dynamic, right-click disk 0, set up mirror. Done.

However this guide indicates a very different route:
https://learn.microsoft.com/en-us/t...kup-and-storage/establish-boot-to-gpt-mirrors
TLDR: "I'm sorry Dave, I can't do boot partition mirroring but I'm not going to explicitly say that"

There's a whole bunch of guides on the MS site regarding the latter route but they all have the same core instructions on the key point of making sure the second disk is capable of booting on its own.

- edit -

I know that full boot drive software mirroring works on Win10 Pro as I've done it in a VM before. I just tried it with the same VM (MBR partition layout), and it worked fine / exactly as I expected it to work from experience. I then set up a second Win10 Pro VM with EFI, verified the GPT layout, attempted to mirror the boot partition but none of the options in Disk Management are available for that partition, nor does it work via diskpart.

I suspect that GPT full boot mirroring can't be done, I just don't have the foggiest idea why (in terms of a technical reason why not, aside from MS couldn't be bothered).

 

[mikeymikec]

A helpful update to anyone thinking of trying this on Win11 or WinSrv2022:


Don't. Somewhere on the MS site it says that dynamic disks are a depreciated feature, which is another way of saying "here be dragons".


I got it working absolutely fine, but Win11 refused to do feature updates with C drive mirroring enabled, and WinSrv2022 throws warnings all the time about the mirroring and defecated in its own bed while I was copying about 150GB of files from and two the same volume, then marked one of the disks as offline (the drive is actually fine) and refused to have anything further to do with it.


If you want further information about how to do this highly inadvisable thing, no you can't mirror the EFI boot partition but you can copy the files from one boot partition to the other so they're sorta mirrored! Also, I never tried to mirror the recovery partition, it's probably the same old mess there but worse.


One "amusing" thing that happened today when I had the Win11 PC up to un-screw its configuration was that after spending some time ensuring that the boot 'mirror' was definitely working, I pulled the second drive, successfully updated Win11 23H2 to 24H2 without any drama, then out of curiosity I ran defrag and Windows said that "optimisation is not available". The disk is still 'dynamic' (read: has cooties), so I delved down the route of undynamic'ing the disk without wiping it (NIUBI Partition Editor Free can do it). It's times like this when having a mirrored setup is actually quite handy! I swapped the first drive out for the second, tried this program out on it, it worked, so I switched back to the first drive and ran it there


After I did all of that, the defrag utility reckoned the drive had been optimised 21 days ago. <Nelson meme "HA HA!".jpg>


I've yet to completely un-screw the WinSrv2022 configuration. I've been testing various plans on a spare PC at home because the server is a live server on a small office LAN and there's no way I'm going to YOLO my way through that and hope for the best.