Adding a HDD to EX4 Spanning

Hi WD Community,

I have a MyCloud EX4 at home with two 1TB hard disks in the 4-bay drive running in spanning mode.

I would like to add a another disk to the unit, can this be done without having to wipe the entire volume? My understanding is that it might be possible as the data is written to the first drive until full, then it starts writing to the second drive.

Worst case scenario I have to copy off what is already on the two 1TB drives, format the entire volume then add the new drive.


See the dedicated EX4 subforum where people more knowledgeable may be able to assist or where you can search for past discussions that may be similar to yours. This subforum (My Cloud) is generally for the single bay/single drive My Cloud devices.

It depends on what you want to achieve. Do you want this new disk as an extension of your current span? If yes, then you have to format all and create a new span containing the 3 disks.

If you don’t need the new disk as part of the existing span, then you can just add it but it’ll be a sperate volume.