I’ve been using Rockstor on Xen, where it was working approximately fine, but I’m trying to switch to Proxmox. System specs below. I’m installing Rockstor on an sdd and using an hba (passthrough) for the actual storage (only two hdds, at the moment). So, the problem: everything installed just fine and booted perfectly. Then I passed the hba through to my rockstor vm. It didn’t boot. Ok, reinstall. Worked fine until the reboot and then it won’t boot. The installer sees the intended boot drive and will install there and it sees the passed through drives.
It’ll install with no errors but won’t boot from the drive it just installed to. In the absence of the passthrough, the sdd comes up as bootable in the boot manager. With the passthrough, it does not. So I don’t think this is really a Rockstor error per se, but something weird where the installer not setting the ssd as bootable, but only when the passthrough is present.
I have no ideas, but would appreciate any advice. FWIW, my Linux skills are shaky. I’m decent enough to play around, but I know just enough to be dangerous. 
Intel D-1508 (Supermicro)
LSI 9300 hba
WD ssd (M.2)
IBM SA120 enclosure (yes, it’s horrible overkill, it was cheap)
Proxmox 4.4
Most recent Rockstor installer
Edit: autocorrect