Re: [Libguestfs] [PATCH] v2v: Add --print-estimate option to print source size estimate.
On Tue, Aug 14, 2018 at 09:31:06PM +0300, Nir Soffer wrote:
On Tue, Aug 14, 2018 at 8:29 PM Richard W.M. Jones
<rjones(a)redhat.com>
wrote:
> This option prints the estimated size of the data that will be copied
> from the source disk.
>
> For interest, the test prints:
>
> 3747840 ../test-data/phony-guests/windows.img
> Estimate: 3710976
>
Why not use qemu-img measure on the overlay?
Yes this would be better, but oddly it doesn't work properly when
the output format is set to 'raw':
/usr/bin/qemu-img 'measure' '-f' 'qcow2' '-O'
'raw' '--output=human'
'/home/rjones/d/libguestfs/tmp/v2vovl62b7c2.qcow2'
required size: 6442450944
fully allocated size: 6442450944
However it's OK if the output format is set to 'qcow2':
/usr/bin/qemu-img 'measure' '-f' 'qcow2' '-O'
'qcow2' '--output=human'
'/home/rjones/d/libguestfs/tmp/v2vovla53d7c.qcow2'
required size: 1047986176
fully allocated size: 6443696128
I guess it ignores sparseness of raw images, but I can't see a way to
specify that on the command line.
OTOH the qcow2 figure is probably a good enough guess for our purposes
(ie. estimating how much data will be copied).
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-p2v converts physical machines to virtual machines. Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.
http://libguestfs.org/virt-v2v