I have the original 4TB MyCloudEX2 (not Ultra) which came with 2 X 2TB WD Reds which I’d like to upgrade to larger drives.
Will two WD 8TB Red Plus drives be supported by this unit?
Can’t find any spec sheets showing limits of HD size.
-M
Seems to be fine to use a pair of 8TB disks, make sure the RAM is maximized to improve performance
Yes, they will work just fine (I had 2x10TB in mine). However, I’d cut my losses and dump the box rather than spend a lot of money upgrading the drives. Support and all remote connection to this device will cease in April.
Get a Synology and be happy!
Thanks for the heads up. Admittedly, I have had issues with the EX2 series 
Am looking at Synology right now.
-M
