Getting strong Frostpunk vibes from when I overloaded The Generator, and left it going just a bit too long. Its plausible the refinery was running close to its production limits given the situation. Environment Victoria blamed aging infrastructure so a combination of factors seems possible. It first opened in 1954.

If you end up with a second proxmox server with its own storage for redundancy in a cluster then ZFS is great. You can mirror each VM. The only issue is the ZFS storage needs to be named the same. But it can be a different size or media.