Hard Drive Compatibility for My Cloud PR2100

My Cloud OS 3 Personal & Network Attached Storage My Cloud Pro Series
3

I ended up successfully upgrading to two WD Red 10TB hard drives. I followed the instructions from e30legacy here: Increase storage on PR2100...help please! - #9 by e30legacy
Navigate to NAS dashboard > Storage > Make sure Auto Rebuild is “On” > Make sure Raid 1 is selected > Check the box labeled “Expand Capacity” > Click “Next” and follow instructions.
You will be prompted to eject one drive from your NAS and insert the new higher capacity drive. It is a long process, took the better half of a day for me with about 6 TB of data across my original 2 drives. Make sure to turn off Plex or any other apps before this process to ensure a smooth process. I’m not sure how the PR2100 will react to Hard Drives above 10 TB, but 10 TB drives worked for me. Now I’m sitting pretty with 20 TB of storage. Not too shabby! Hope this helps. Good Luck!