Proxmox is an outstanding virtualization platform. It has a number of great features that you don't get in many other enterprise platforms. One of these features is Ceph support, including the ability to run Ceph on the Proxmox nodes themselves. In addition to using Ceph for my VM's and Containers, I wanted to take advantage of the Ceph Object Gateway to get S3 compatible storage for my websites.
There are good reasons to have your directory on a separate partition in CentOS, which is the default when you install. However sometimes, you just need the entire drive on the same partition. I ran into this while installing OpenStack, and it's one of the first things I do to prep an RDO `packstack` installation.