Problem with the size of hardrive

I have a MyCloudEX2Ultra and had it for about 7 years or so. One of the drives went bad. They both where 4 tb WD drives. So I replace the bad one with a WD Black 6 tb drive. I see in the setting page for the MyCloudEX2Ultra it shows the 4 tb and the 6 tb. But in Windows it shows the 4 tb drive. The problem is the 6 tb now shows as a 4 tb drive why? How can I fix this?

Thank you for any help.

Did you run the NAS in RAID mode?

"In a RAID 1 configuration, the size of target disk must be greater or equal to the one of the source disk. Therefore the capacity of the array will be same as the one of the smallest size in the group. "

I did not set it up as raid. I use JBOD. Is that raid? I didn’t think it was.

In this case you should see all sizes independently.
Can you connect via SSH and run df -h?

I see this in the MyCloudEX2Ultra.

Volume_1​ JBOD​ 3.93 TB​ Good

Volume_2 JBOD 5.94 TB Good

And in windows I see each drive. But they are 4 tb each.

I do not know what this is -

Can you connect via SSH and run `df -h

I fix it. Bought a second 6 TB drive.