Re: virt-p2v

[Richard W.M. Jones]

On Thu, Jan 22, 2009 at 10:34:22AM -0800, Brian Krusic wrote:
>  I've used virt-p2v many times with great success.
>
>  However I have an issue.
>
>  I've always converted hosts having small disks of around 35G over to  
>  domUs but have an issue were my current host in need of being  
>  virtualized has a physical disk of 400G but its / partition is only 35G, 
>  the rest of the drive is unallocated/unpartitioned and therefore unused. 
[...]
>  I obviously don't want to migrate the entire 400G disk as it only
> has a 
>  35G root partition (ext3, no LVMs in this case). 
Oh dear, this is a problem :-(

The answer unfortunately is that virt-p2v currently doesn't support
this - we can only migrate whole block devices.

Unfortunately even compression doesn't help very much here.  Even if
the disk is mainly zeroes, the gzip-based compression used doesn't
compress very well, so you'll still have a longish wait.  You can try
selecting compression anyway to see if it helps.

It's on the long to-do list to fix this so that people can migrate
partial disks (including just subdirectories, and excluding
subdirectories).

BTW, if the disk doesn't use LVM, you will need to use version 0.9.9,
uploaded to the website a few days ago, because that fixes a bug
related to having the root partition not being on LVM.

Rich.

-- 
Richard Jones, Emerging Technologies, Red Hat  http://et.redhat.com/~rjones
Read my OCaml programming blog: http://camltastic.blogspot.com/
Fedora now supports 68 OCaml packages (the OPEN alternative to F#)
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virt-p2v

[David Lutterkort]

On Thu, 2009-01-22 at 20:24 +0000, Richard W.M. Jones wrote:
>  On Thu, Jan 22, 2009 at 10:34:22AM -0800, Brian Krusic wrote:
>  > I've used virt-p2v many times with great success.
>  >
>  > However I have an issue.
>  >
>  > I've always converted hosts having small disks of around 35G over to  
>  > domUs but have an issue were my current host in need of being  
>  > virtualized has a physical disk of 400G but its / partition is only 35G, 
>  > the rest of the drive is unallocated/unpartitioned and therefore unused.
>  [...]
>  > I obviously don't want to migrate the entire 400G disk as it only has a 
>  > 35G root partition (ext3, no LVMs in this case).
>  
>  Oh dear, this is a problem :-(
>  
>  The answer unfortunately is that virt-p2v currently doesn't support
>  this - we can only migrate whole block devices. 
As I understand Brian, the block device is whatever / is mounted on, a
25G partition, and it shouldn't matter how big the actual disk is
containing the partition.

David

virt-p2v

[Brian Krusic]

Hi David,

Well, my / is 25G however the image that gets produced is 400G.

The 400G is that actual size of my entire disk but I only have a 25G  
partition defined, the rest of the drive is blank other then for a  
small swap partition.

- Brian




On Jan 27, 2009, at 2:31 PM, David Lutterkort wrote:

>  On Thu, 2009-01-22 at 20:24 +0000, Richard W.M. Jones wrote:
> > On Thu, Jan 22, 2009 at 10:34:22AM -0800, Brian Krusic wrote:
> >> I've used virt-p2v many times with great success.
> >>
> >> However I have an issue.
> >>
> >> I've always converted hosts having small disks of around 35G over to
> >> domUs but have an issue were my current host in need of being
> >> virtualized has a physical disk of 400G but its / partition is  
> >> only 35G,
> >> the rest of the drive is unallocated/unpartitioned and therefore  
> >> unused.
> > [...]
> >> I obviously don't want to migrate the entire 400G disk as it only  
> >> has a
> >> 35G root partition (ext3, no LVMs in this case).
> >
> > Oh dear, this is a problem :-(
> >
> > The answer unfortunately is that virt-p2v currently doesn't support
> > this - we can only migrate whole block devices.
>
>  As I understand Brian, the block device is whatever / is mounted on, a
>  25G partition, and it shouldn't matter how big the actual disk is
>  containing the partition.
>
>  David
>
>

virt-p2v

[Richard W.M. Jones]

On Tue, Jan 27, 2009 at 03:11:16PM -0800, Brian Krusic wrote:
>  Hi David,
>
>  Well, my / is 25G however the image that gets produced is 400G.
>
>  The 400G is that actual size of my entire disk but I only have a 25G  
>  partition defined, the rest of the drive is blank other then for a small 
>  swap partition. 
We completely need a way to manipulate disk images - eg. resize LVM
partitions, read out data from filesystems nested inside partitions
inside LVM, etc etc.  In other words, a non-broken gparted.

virt-df has much of the machinery required to do this.

Turn it into a library, package it up ...  If only I had the time.

Rich.

-- 
Richard Jones, Emerging Technologies, Red Hat  http://et.redhat.com/~rjones
virt-top is 'top' for virtual machines.  Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
http://et.redhat.com/~rjones/virt-top

virt-p2v

[Richard W.M. Jones]

On Tue, Jan 27, 2009 at 10:31:44PM +0000, David Lutterkort wrote:
>  On Thu, 2009-01-22 at 20:24 +0000, Richard W.M. Jones wrote:
>  > On Thu, Jan 22, 2009 at 10:34:22AM -0800, Brian Krusic wrote:
>  > > I've used virt-p2v many times with great success.
>  > >
>  > > However I have an issue.
>  > >
>  > > I've always converted hosts having small disks of around 35G over to  
>  > > domUs but have an issue were my current host in need of being  
>  > > virtualized has a physical disk of 400G but its / partition is only 35G, 
>  > > the rest of the drive is unallocated/unpartitioned and therefore unused.
>  > [...]
>  > > I obviously don't want to migrate the entire 400G disk as it only has a 
>  > > 35G root partition (ext3, no LVMs in this case).
>  > 
>  > Oh dear, this is a problem :-(
>  > 
>  > The answer unfortunately is that virt-p2v currently doesn't support
>  > this - we can only migrate whole block devices.
>  
>  As I understand Brian, the block device is whatever / is mounted on, a
>  25G partition, and it shouldn't matter how big the actual disk is
>  containing the partition. 
Unfortunately not - virt-p2v can only migrate whole disks.

Rich.

-- 
Richard Jones, Emerging Technologies, Red Hat  http://et.redhat.com/~rjones
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into Xen guests.
http://et.redhat.com/~rjones/virt-p2v