Hi ejolaus,
deploying the vAPP Version does mean you will deploy 2 VMs. One is the UI_VM and the other is the Analytics_VM. They come out of the box with a "Basic" Disk to start with (The UI_VM with 140GB and the Analytics_VM with 225 GB). Dont forget to setup up an IP-Pool on Datacenter Level connected to the Portgroup you want to deploy the vAPSS (VMs) on as described in the documentation. After you deployed the vAPP you need to add some more Disks to the Analytics VM where the FSDB reside on. You can add up to 4 Disks, just shutdown the vAPP, add the Disk and start the vAPP again. vCOPS meaning the Analytics VM will detect the Disk and starts to use it automatically. Beware of the DISK IO will you mention on the Disks the Analytics VM is using!