VM showing '/mnt filesystem full' after update to 23.1

[serversonic]

I run a three node Proxmox system with an OPNSense VM as the gateway router. I updated it to 23.1 from the web interface yesterday and it seemed to complete successfully  but on trying to access the web interface this morning I found it wasn't loading properly, and checking the console showed the repeated error '/mnt: filesystem full'. The filesystem is showing 109% for / and other mounts. I saw an issue that suggested that that required a firmware update on the host, so I did that but the problem persists. I can resize the VM but I suspect this isn't the case.
Routing components are still working but practically everything else is complaining.

[serversonic]

It was indeed a space problem - I created my VM with a standard 32GB Proxmox image (following one of the top search results - HomeNetworkGuy I think), and v23 does indeed need a minimum of 40GB. I did a clean install on a bigger VM and restored the backup I took before upgrading and it Just Worked.
I did try increasing the disk size and indeed mounting a another disk device but actually doing that on a FreeBSD disk isn't easy in Proxmox.

[cookiemonster]

Something is eating up your disk space. The OS needs only a couple of Gigabytes of space, obviously more for packages, etc. Excessive Logging is normally the culprit, meaning you might end up with the same situation again.
Nothing to do with OPN versions.