Windows 10 RAID1 Creation Error

[GreenFluorite]

I have two identical 2TB SSDs. Disk 0 contains the OS and some data, and Disk 1 is all unallocated space. I want Disk 1 to be a mirror of Disk 0. When I right-click on Disk 0 and choose Add Mirror, it recognizes Disk 1 as the likely partner, warns me of the conversion to dynamic disks, and then promptly tells me "There is not enough space available on the disk(s) to complete this operation." Disk 0 contains a 1862.45 GB primary partition, 530 MB recovery partition, and 50 MB System Reserved. Disk 1 is 1863.02 GB unallocated, which, by my calculation, is equal to the sum of the Disk 0 partitions. I tried shrinking the partition I'm trying to mirror. I sliced 20 GB off of it, and at 1842 GB it still tells me the proposed 1863 GB destination disk does not have enough space. What could be the problem?

 

[Neemobeer]

Are they the same make/model disks?

 

[GreenFluorite]

Yes, they're identical Samsung 870 EVO SSDs.

 

[Neemobeer]

I don't have a setup to test. I imagine it needs to store some extra data regarding the raid causing the 'not enough space' error. Did you try disk mirror or volume mirror? You may also try to use storage spaces which is typically the preferred method in the absence of hardware raid capabilities

 

[GreenFluorite]

I'm simply going into the Disk Management interface, right-clicking on the C: partition of Disk 0, choosing "Add Mirror" (see attached screenshot), picking Disk 1 as the mirror location, accepting the warning that the process will turn them from Basic to Dynamic disks, then getting the error that there isn't enough space.