I wish I knew ... at least it was a span volume so we could use proxmox support for vmdk and achieve about 30 minutes of planned downtime but a week of storage vmotion followed by another week of the proxmox equivalent.
When I get back to work I will finish the samba configuration of the ceph cluster front-ends to replace those elephants.
Why? Honest question, what leads to that Kind of size and why cant it use NAS shares or SAN disks for most of that data? Kudos on the migration!