Thanks it worked on
Version 4.5.6-1.el9, CentOS 9


De: "Gianluca Cecchi" <gianluca.cecchi@gmail.com>
Para: "suporte" <suporte@logicworks.pt>
Cc: "users" <users@ovirt.org>
Itens enviados: Quinta-feira, 28 de Novembro de 2024 12:22:31
Assunto: Re: [ovirt-users] Changing Disk Alocation Policy

On Thu, Nov 28, 2024 at 11:42 AM José Ferradeira via Users <users@ovirt.org> wrote:
Hi,

It's possible to change a  thin-provision disk to a preallocated disk?

Storages are ISCSI

Thanks



there was an old thread about it at the time of 4.0/4.1. 
What it worked and I verified still works in 4.5 is:
VM is powered on or off (with pros and cons for both scenarios in case of production machine)
create a snapshot of the VM 
select the snapshot line under snapshots and select clone button
in resource allocation section of the new vm screen change allocation policy for the desired disk/s from thin provision to preallocated
Then you can decommission old VM and use the cloned one

HIH,
Gianluca