External HDD for both backup and expansion in WD My cloud

I have WD my cloud 2TB and I have attached 2TB external HDD for backup purpose. Now I have run out of space. Would it be possible to attach 4TB HDD such that 2TB is used for backup of my cloud and rest of 2TB will be used for expansion? The only caveat would be that 2TB additional would not be back up?

Or should I attach 2 HDD using USB hub such that one is used for backup other for expansion?

Which method is possible and advisable? And can I use media server capability on additional HDD?

When attaching an external USB hard drive to the USB port on the My Cloud, the USB drive will be seen as another Share. It technically does not “expand” the size of the existing hard drive in the My Cloud. What it is doing is providing another location (Share) where the user can store user data and or use as a Safepoint / Backup location for the My Cloud.

If one enables USB Content Availability in the My Cloud Dashboard > Settings the My Cloud Dashboard Capacity chart will add the USB drive and it’s free space to the chart’s calculations.

The My Cloud User Manual explains in general terms how to attach and use a USB hard drive on the My Cloud.

Also make sure the USB hard drive is formatted in a supported My Cloud format otherwise the My Cloud won’t be able to properly access the USB drive.