Actual size is the size that is actually allocated in the disk, if you create a thin provisioned 20GB disk for instance its actual size before installing an OS on it will be 0 bytes, after installing the OS it's expected to have a value in the actual size

On Fri, Jan 20, 2017 at 7:45 PM, Jakub Niedermertl <jniederm@redhat.com> wrote:
Hi Tal,

what describe values in column 'actual_size' of view 'all_disks_for_vms'?

I noticed very strange behavior of values in this column: It's
* 0 for 'thin-provisioned' disk of VM in cluster 4.1
* 2147487744 for 'preallocated' 2GB disk of VM in cluster 4.1
* 0 for 'thin-provisioned' disk of VM in cluster 4.0
* 0 for 'preallocated' disk of VM in cluster 4.0
* 0 for disk of template that was created by importing glance image as
template to 4.0 cluster
* 200704 for disk of template that was created by importing 12 MB
glance image as template to 4.1 cluster
* 0 for disk of template that was created by importing glance image as
template to 4.0 cluster
* 0 for disk of template of VM with preallocated disk in 4.1 cluster
* 0 for disk of template of VM with preallocated disk in 4.0 cluster

How is the value supposed to be computed?

Thanks for explanation

Jakub