This is precisely what I plan on doing when I eventually launch my app. I have 3x Dell R620s in a Proxmox cluster running K8s nodes, Ceph on NVMe with CSI-RBD,

This is precisely what I plan on doing when I eventually launch my app. I have 3x Dell R620s in a Proxmox cluster running K8s nodes, Ceph on NVMe with CSI-RBD, and a separate Supermicro 2U exposing ZFS for spinning storage. The only missing link is 10G networking, because 10G switches aren’t super cheap.