Hi,
I would like to make a encryted raid 1 system with the raid box set and two 6TB WD-red drives.
I wanted to make it for a long time now but according to those threads there have been problems:
https://forum.test.turris.cz/t/nas-setup-in-raid1-with-disks-2tb-possibly-with-encryption/1357
https://forum.test.turris.cz/t/sata-hdd-issues/1173
Were those problems solved in the meantime?
I read the second thread and it didn’t make me wiser 
What i would do is:
mdadm --create /dev/md0 --level=mirror --raid-devices=2 /dev/sda1 /dev/sdb1 cryptsetup luksFormat -c aes-cbc-essiv:sha256 -s 256 -h sha256 -y /dev/md0 cryptsetup luksOpen /dev/md0 raid mkfs.ext4 -m0 /dev/mapper/raid mount /dev/mapper/raid /media/disk
If the problems that appeared in the mentioned threads are solved I would order my HW-drives and remodel the NAS box to make the fan more quite. (well the fan itself is quiet, but it gets loud when it sits directly on the perforated metal plate of the NAS box).