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I have the following setup:

  • Two identical NVMe disks of about 1TB size
  • Windows 10 Education N version 2004 (latest version as of writing this question as far as I'm aware)
  • A fresh install using UEFI on disk 0 using the following partitions:
Partition ###  Type              Size     Offset
-------------  ----------------  -------  -------
Partition 1    System             100 MB  1024 KB <= EFI
Partition 2    Reserved            15 MB   101 MB <= MSR
Partition 3    Dynamic Data       249 GB   116 MB <= Windows installation
Partition 4    Recovery           513 MB   249 GB <= Recovery

I tried following this guide from Microsoft but it doesn't seem to be entirely up to date with the 2004 version of windows. I can follow the steps fine up to step 8 where I'm supposed to use the command

C:\>xcopy p:\*.* s: /s /h

to copy the data from the existing EFI partition on disc 0 to its new counterpart on disk 1. If I try that, I'm getting the error

P:\EFI\Microsoft\Boot\BCD
Sharing violation

I tried doing the same while using a shell from the installation medium and it copied 139 (IIRC) instead of the expected 7 files and then I got stuck again at the following step which is the actual mirroring via

DISKPART> Select volume C
DISKPART> add disk=1

which resulted in the error message

Virtual Disk Service error:
The disk's extent information is corrupted.


DiskPart has referenced an object which is not up-to-date.
Refresh the object by using the RESCAN command.
If the problem persists exit DiskPart, then restart DiskPart or restart the
computer.

A very similar guide from http://woshub.com/software-boot-mirror-gpt-windows/ didn't have the copying step but failed when trying to do the mirroring too.

Is there any up to date information on how to create a mirror of the boot partition using GPT on Windows 10 version 2004?

If I forgot some vital information about the system, please let me know and I'll try to update the question accordingly.

Midnight
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  • You tagged RAID-1 but didn't include anything about a raid in your question. RAID-1 is indeed mirroring. Although, I believe you have to create the RAID first, then install your OS. The raid controller will automatically do the mirroring. I'm personally not aware of a method of manually mirroring a disk, then creating a RAID volume from two mirrored disks. When you go to create the array, the data is going to be erased from the disks. If you just want to clone the disk for backup purposes, there are apps for that. – Jim Diroff II Aug 24 '20 at 16:18
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    @JimDiroffII I'm not talking about a hardware raid I want to do a pure software raid using the tools that come with Windows 10. I know that it works and I managed to get a similar (if not exactly the same) configuration to run on another server with an older version of Windows 10. I don't believe that the term raid-1 strictly applies to hardware raids, so I don't think I should remove the tag. – Midnight Aug 24 '20 at 18:43

1 Answers1

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I finally got the mirroring to work. The trick was to convert the second disk back from dynamic to basic. Basic disks can't be mirrored or striped but the error telling me that there wasn't enough free space on the disk each time I even just tried to create a simple volume went away. Next I deleted the simple volume again, converted the disk back to dynamic and now all of sudden both - creating a simple volumen and mirroring the volume on the first disk - worked just fine. I'm pretty sure this erratic behavior is not working as intended, so there's no telling whether it will stay this way or not.

Midnight
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