DS full with only 2 VM

Hi,

I have a Dell VRTX with 3 x 300G hdd. I setup a virtual disk with raid 0.

On poweredge server (in VRTX), I installed Esxi6.5 and then installed vCenter, and create another VM.

I want to create another VM, but get error that is not enough space.

What is the other partition? How can I use that space for VMs?

Thanks in advance.