Hi! I just registered to chime in as I had the same issue and MAYBE someone googling this will end up here.
Background: I have Multiple drives in a couple of ZFS arrays. I use OMV mainly because I like the interface and I'm familiar with Linux tools.
Issue / Fix: I had the same exact error message as posted here but in my case, the issue was related to updating the kernel. I use Proxmox kernel and all I needed to do to fix the issue was to re-install proxmox kernel through the interface.
I went through a few hoops before I though of that since I'm retarded but hopefully you won't have to if you're reading this. FYI, this "issue" (or user config error) will cause all sorts of problems, none of which will mention zsf, proxmox or anything related.
Hope that helps!
Many thanks for this, i had the same issue.