I have a 4TB MyCloudMirror (2 x 4TB hdd) in RAID 1 configuration and it is nearly at full capacity. Can I add a 2 x 4TB MyBook Duo via USB to increase the capacity of my MyCloudMirror to 8TB. I understand the RAID 1 mirror will run independently in the two devices, that’s no problem.
It might or might not work. If you test this, make sure that the drive is formatted on one of the followings formats.
NTFS (read and write capability)
Linux Ext2, Ext3/Ext4
I haven’t test this. However, I don’t see a reason why it shouldn’t work.