VirtIo errors inside VM with UFS-in-zvol

Nikolay Denev ndenev at
Sun Aug 24 13:05:25 UTC 2014

On Wed, Feb 19, 2014 at 6:38 PM, Stephen Stuart
<stephen.stuart at> wrote:
> I have VMs running on FreeBSD 10.0, for which I made zvols to provide the
> block IO device for bhyve. When I boot from the installation ISO, gpart
> works inside the VM, but newfs does not, reporting vtbd0 errors. Likewise,
> dump does not work inside the VM (failing with too many vtbd0 hard errors),
> but if I shut down the VM and dump the filesystem by specifying the
> partition name in the host machine's ZFS space (/dev/zvol/zroot/VOLNAMEp2),
> dump works just fine.
> With a different VM, where I got smart and did all the gpart and newfs work
> outside the VM:
>     zfs create -V 10g zroot/WORKING
>     gpart create -s GPT /dev/zvol/zroot/WORKING
>     gpart add -t freebsd-boot -s 64k /dev/zvol/zroot/WORKING
>     gpart add -t freebsd-ufs -s 7525m /dev/zvol/zroot/WORKING
>     gpart add -t freebsd-swap /dev/zvol/zroot/WORKING
>     newfs /dev/zvol/zroot/WORKINGp2
> then install works fine inside the VM when I mount the filesystem and
> create fstab by hand, and dump inside the VM works fine.
> There's a somewhat related post here:
> but I don't see anything specific to this issue. I'd like dump from inside
> the VM to work, the fact that it doesn't makes me concerned that there are
> issues lurking that might lead to data loss. Where do I go from here?
> Thanks,
> Stephen
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> freebsd-virtualization at mailing list
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Just to say I'm seeing the same issue.

I want to create i386 virt on an amd64 host, and downloaded

I've created a zvol:
  zfs create -V20G zfs/freebsd-i386

Then starting bhyve:
  sh /usr/share/examples/bhyve/ -m2048m -d
/dev/zvol/zfs/freebsd-i386 -I FreeBSD-10.0-RELEASE-i386-disc1.iso -i

Installer starts, I'm going with the default of GPT partition using
the whole disk, but then I get this error:
  Error mounting partition /mnt:
  mount: /dev/vtbd0p2: Invalid argument

Trying to mount the partiton from the shell produces the same error,
and in dmesg I see this:
  vtbd0: hard error cmd=write 290-305

Running newfs outside of the virt works, and then I can mount inside
the virt and installer continues.

I'm running:

FreeBSD nas.home.lan 10.0-STABLE FreeBSD 10.0-STABLE #13 r270295M: Thu
Aug 21 22:05:37 UTC 2014
root at nas.home.lan:/usr/obj/usr/src/sys/NAS  amd64


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