Windows 10 dynamic mirror showing “Failed”

Although the Windows Disk Management does not allow the resize of dynamic disks, some third party tools claim that ability.

Some of the better-known ones are :

EaseUS Partition Master (free) - see the article How to resize dynamic volume?
AOMEI Partition Assistant (Home version is free but unclear if can resize dynamic disks)
AOMEI Dynamic Disk Manager ($36 with trial)

If the tools can as advertised shrink the dynamic disk, the resulting unallocated space can be used in a new partition.

[EDIT1]

I still have the feeling you have it backward: I believe that the quoted Microsoft text meant that you create the dynamic disk over the entire physical disk, then allocate a volume in it and use that volume in a non-Windows OS.

Some recent Linux distributions understand dynamic disks, but I don't know to what degree. Otherwise you might need to find out which physical sectors are occupied by the volume(s) and mount in Linux as as a raw device (horrifying even if possible).

[EDIT2]

You wish for a separate RAID for Windows-only, which requires dynamic disks, which are a proprietary Windows format, not well-supported by Linux.

Below is an idea for another solution. This solution will require studying and trying - I have never done it and so can't offer a cookbook.

The idea is to use an advanced boot manager such as Grub4dos, that can hide/unhide partitions depending on the OS booted. It can also map partitions and do disk emulation. You might be able to use it to fool Windows into thinking that two partitions on two disks are each the entire disk (Windows will not see the rest of the disk), so you could set up dynamic disks on the two virtual disks without affecting Linux which will be using the rest of the physical disks.

Try to convert dynamic to basic using the Windows interface:

1. Back up all volumes on the disk you want to convert from dynamic to basic.
2. Open Computer Management (Local).
3. In the console tree, click Computer Management (Local), click Storage, and then click Disk Management.
4. Right-click each volume on the dynamic disk you want to convert to a basic disk, and then click Delete Volume for each volume on the disk.
5. When all volumes on the disk have been deleted, right-click the disk, and then click Convert To Basic Disk.

Command line should Works on Windows 10. This link refers to Windows Server 2003.

command line how to

If you can´t or you want to save your data, then try testdisk tool. It worked fine for me both to recover data and to convert dynamic to basic without data loss. In this case, backing up is optional but always recommended.

testdisk download

testdisk-how to