[virt-tools-list] virt-manager not really allocating disk space

[Michal Privoznik]

On 19.02.2013 13:19, Peter Velas wrote:
> Hello guys,
> 
> 
> My environment
> Fedora 18 with kernel   3.7.8-202.fc18.x86_64
> Virtual Machine Manager 0.9.4
> 
> when creating New Storage Volume in virt-manager
> newVM.img with qcow2 format  for example with following settings:
> 
> 
> Max Capacity: 10240  MB
> Allocation: 10240 MB
> 
> But then if I check the file its still small
>  ls -lha newVM.img
> -rw------- 1 root root 193K Feb 19 12:59 newVM.img
> 
> So I am not sure if its bug or this feature isn't implemented yet.
> qemu-img create / convert preallocation is working fine.
> 
> 

In fact, this is feature. QCOW images are dynamically allocated as the
amount of written data grows. If you don't want this behavior, you can
check the 'Allocate entire disk now' checkbox in the 4th step when
creating a new domain. However, be aware that allocating huge files may
takes some time. But on the other hand, guest IOs are not delayed as if
they were in case of self allocating QCOW.

BTW: you can always check QCOW disk size via:

  qemu-img info /some/path

Michal