Switching from IDE to virtio_blk [qas Re: [Fedora-xen] Goodbye Xen on RH/Fedora?]

[Richard W.M. Jones]

On Wed, Jan 21, 2009 at 03:06:43PM +0100, Emre Erenoglu wrote:
> On Wed, Jan 21, 2009 at 2:48 PM, Mark McLoughlin <markmc at redhat.com> wrote:
> 
> > (This is all getting offtopic for fedora-xen, we should really move to
> > fedora-virt)
> >
> > On Wed, 2009-01-21 at 14:28 +0100, Jan ONDREJ (SAL) wrote:
> > >  virtio_net works well, but I have trouble to boot from virtio_blk.
> > >
> > > I can add second disk as virto block device, but I can't boot from
> > > first disk.
> >
> > When switching from IDE to virtio, you need to first build a new initrd
> > in the guest with e.g.:
> >
> >  $> mkinitrd --with virtio_pci --with virtio_blk -f
> > /boot/initrd-$(kernelversion) $(kernelversion)
> >
> > You only need to do this once. After that, if a new kernel is installed
> > while you're booted off a virtio disk, then mkinitrd will include the
> > modules automatically.
> 
> 
> You will also need to specify /dev/vdX on the kernel  root= line and make
> sure your init script inside your initrd triggers the virtio drivers at boot
> so that the /dev/vdX are created.

Yes I have to agree with Emre here - I don't think it's as simple as
just rebuilding mkinitrd.  I got that far but gave up later on.

/me checks notes ...

Yup, I got as far as working out that you would have to edit fstab and
possibly /boot/grub/device.map and /boot/grub/menu.lst, before giving
up.

If anyone would like to fill in the wiki page here on the subject:

  http://wiki.libvirt.org/page/Virtio

I'd like to reiterate that _none_ of this complexity is required when
installing a new guest.  Anaconda sets up everything for you.

Rich.

-- 
Richard Jones, Emerging Technologies, Red Hat  http://et.redhat.com/~rjones
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