I've got 73 vms running on a production hypervisor (lvm-backed storage) and using their methods it's averaging 433.1 GiB/day over the disks for the VM storage. I don't know how they're managing double that hosting a blog.

The "server which runs my blog (among many other things)" probably has most of it's writes from a mail server for dozens of domains and has some commercial web sites that are very interactive and database backed.

Maybe they're backing up the SHA256 hash of every byte it sends or receives?