proxmox 7.1-2

Hi Proxmox, I had 3 SSD and will create a RAID-5. The usable size roughly will be 2TB after the RAID. I want to share 2TB for OS, VM and Backup by using partitioning during the pve installation. 1. What is the recommended pve OS disk size/partition? 2. What is the disk format should i use...