If you use the standard partition layout you will get an LVM setup with one logical volume each for / (pve-root, for the host operating system and programs), /var/lib/vz (pve-data, for VM/CT disks, templates, backups, ..) and swap (pve-swap). Only pve-data is configured as local storage by default. You can check the size of the LVs with "lvdisplay pve".