Install Windows 10 or Server, have both drives installed into the system.
Disable hibernation function
powercfg.exe /h off
Start Windows and open disk management
Note the Disk #, in this case its Disk 1. You'll need this later.
now right click on your current boot drive and select properties
verify you have an UEFI based system here, it should be GUID/GPT
open cmd.exe as admin,
Type the following: (use correct desk # from step 1 above)
diskpart
select disk 1
select partition 1
detail partition
Write down the Type ID of the recovery partition and its size
Now convert the disk you would like to mirror to GPT and create a recovery partition. (use the correct disk # and size)
Select disk 2
convert gpt
select partition 1
delete partition override
create partition primary size=300
format fs=ntfs quick label=Recovery
select partition 1
set id={use your drives ID}
Now assign drive letters to both disks (using your correct disk #'s)
select disk 1
select partition 1
assign letter=x
select disk 2
select partition 1
assign letter=y
exit
Copy the data,
robocopy x:\ y:\ * /e /copyall /dcopy:t /xd "System Volume Information"
Now to mirror system volume,
diskpart
select disk 1
list part
Write down size of system and reserved partitions from your current boot drive.
now create system and reserved partitions on the drive you would like to be the mirror,
select disk 2
create partition efi size=99
format fs=fat32 quick
assign letter=w
create partition msr size=128
now assign a drive letter on your current boot drive
select disk 1
select part 2
assign letter=z
exit
Almost done now... Don't you wish your system had an nvme m.2 raid controller?
Now copy EFI from boot to the mirror,
robocopy z:\ w:\ * /e /copyall /dcopy:t /xf BCD.* /xd "System Volume Information"
now close cmd and open the disk manager, diskmgmt.msc or from computer management.
right click on your boot disk and choose convert to dynamic disk
the correct disk should already be selected, click OK, Convert, and then finally Yes.
Now do the same with the disk that will be the mirror,
again the correct disk will be selected already, click OK, Convert, then Yes.
At last, we can setup the mirror,
right click on your boot drive partition and choose Add Mirror, select the correct drive and click Add Mirror.
Now open diskpart and remove the extra drive letters,
diskpart
select disk 1
select part 1
remove letter=x
select part 2
remove letter=z
select disk 2
select part 1
remove letter=y
select part 2
remove letter=w
You're done!