Disk size not fully shown

Hello, I am new to dedicated seedboxes and very greatful for such a solution as Quickbox. However I seem to have messed up the installation.
My disk size is 6 TB. (2 x 3.0)
However, disk usage shows max size of 1.0 TB.
Have I installed quickbox on wrong partition or something? I’m confused about this.

this is what df command shows on online console.