Foreword: As much as I tried to search the internet, most of the tutorials are for regular smaller than 2TB drives. And there are tons of forum posts that say "use hwraid". And I found a method that worked for me, see the 'dd method', but I am sure there are more clever ways of doing this.
Because actually, you do not need much at all. One simply needs a valid RAID1 mirror of the data on the disk, the Reserved partition can stay as it ever was. But achieving this is not so simple.
The Windows diskpart trick:
https://silvenga.com/raid1-windows-server-2016/
When the tutorial shows "convert dynamic", I had to issue "convert gpt" before hand. But then the command executed. All is fine, until I hit the marking partitions active (so the system would actually boot). Then it starts to throw errors that it cannot mark "non-fixed drives" active.
The dd method:
Weeks ago when I had a similar project I used dd to just clone the layout from one drive to another. Back then the Disk Manager happily found both drives. I removed the C: (data) partition from the second drive, started a new mirror, and it was OK. (If you remove the drive, you have an intact boot and the good layout, so you can just dd back for example.)
But now, I tried the dd method and the Disk Manager keeps saying the disk is Offline, it's Invalid, and all that. And of course having to dd a few terabytes drive is never fun, can take up to 6+ hours even.
The sfdisk method:
Tried saving /dev/sda partition layout and then writing it to /dev/sdb, but same "invalid drive" problem.
My question is. What is a proper way to set up a >2TB SWRAID1 in Server 2016?
Ps.: If you simply leave the second drive empty, and just have the Data partition mirrored, the layout will look all different. So good luck mirroring or copying that back. It's simply impossible.
