Problem Booting Migrated SCO OpenServer 6 VM: “vfs_mountroot: cannot mount root”

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M.Bergmann

New Member
Aug 5, 2025
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Hi everyone,

we’re currently facing an issue after migrating a legacy SCO OpenServer 6 virtual machine from VMware to Proxmox. Here's what we’ve done so far:
  • Successfully converted the original .vmdk file to .qcow2 using qemu-img.
  • Created a new VM in Proxmox and attached the converted .qcow2 disk.
  • The VM does start, and we can see the initial OpenServer boot splash.
  • However, shortly after, the boot process fails with the error:
vfs_mountroot: cannot mount root

We've tried different hardware configurations (IDE, SATA, SCSI, etc.), adjusted boot options, and tested various machine types and BIOS/UEFI settings — but nothing has worked so far.

Is there anyone who has successfully run SCO OpenServer 6 on Proxmox or dealt with this specific issue? Could this be a compatibility limitation due to the age of the OS?

Any suggestions or tips would be highly appreciated.

Thanks in advance!
 
M.Bergmann said:
Hi everyone,

we’re currently facing an issue after migrating a legacy SCO OpenServer 6 virtual machine from VMware to Proxmox. Here's what we’ve done so far:
  • Successfully converted the original .vmdk file to .qcow2 using qemu-img.
  • Created a new VM in Proxmox and attached the converted .qcow2 disk.
  • The VM does start, and we can see the initial OpenServer boot splash.
  • However, shortly after, the boot process fails with the error:
vfs_mountroot: cannot mount root

We've tried different hardware configurations (IDE, SATA, SCSI, etc.), adjusted boot options, and tested various machine types and BIOS/UEFI settings — but nothing has worked so far.

Is there anyone who has successfully run SCO OpenServer 6 on Proxmox or dealt with this specific issue? Could this be a compatibility limitation due to the age of the OS?

Any suggestions or tips would be highly appreciated.

Thanks in advance!
Click to expand...

I went this route and got nowhere - no combination of bootstrings will allow you the get the proper HBA driver to get OSR6 and Proxmox to work together. Lot of time sunk on that.

Need virtio scsi driver for HBA and paravirtual driver for NIC

However, all is not lost - assuming you are on latest & greatest OSR6 (definitive 2018, fully patched), there is a boot ISO Xinuos created just for this.
See:https://wdb1.sco.com/kb/showta?taid=128148

Note, however, that KVM, which proxmox uses, is not part of the standard OSR6 license, it requires an add-on license. Following the above will get you a 30 day trial license, you'd need to purchase license to get to permanent functionality.
 
A horrible kludge, but I use nested virtualization using Proxmox to run Openserver 6 within an ESXi VM.

I spent a lot of time trying a fresh Openserver 6 install as well as a migration of existing VMware Openserver 6 installation to Proxmox using a virtualized MegaRAID SAS 8708EM2 controller and the latest SCO MegaRAID driver without success. I even bought a MegaRAID controller which I passed through to the Proxmox Openserver 6 VM without success.

I'm a hobbyist, so the purchase of OpenServer 6 Definitive wasn't an option.
 
Used to be you could run it in virtualbox, but I'm told a recent change in virtualbox makes it no longer supported/viable.

If you're like me and you waste time installing things as 'proof-of-concept', you can probably pull the most recent version off Xinuos website, bypass licensing, and get 30 day demo for free. Alternatively, if you are a reseller, you could email them asking for an NFR copy.
 
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