I have a source oVirt environment with storage domain on FC

I have a destination oVirt environment with storage domain on iSCSI

The two environments can communicate only via the network of their respective hypervisors.

The source environment, in particular, is almost isolated and I cannot attach an export domain to it or something similar.

So I'm going to plan a direct move through dd of the disks of some VMs

The workflow would be

On destination create a new VM with same config and same number of disks of the same size of corresponding source ones.

Also I think same allocation policy (thin provision vs preallocated)

Using lvs -o+lv_tags I can detect the names of my origin and destination LVs, corresponding to the disks

When a VM is powered down, the LV that maps the disk will be not open, so I have to force its activation (both on source and on destination)

lvchange --config 'global {use_lvmetad=0}' -ay vgname/lvname

copy source disk with dd through network (I use gzip to limit network usage basically...)

on src_host:

dd if=/dev/src_vg/src_lv bs=1024k | gzip | ssh dest_host "gunzip | dd bs=1024k of=/dev/dest_vg/dest_lv"

deactivate LVs on source and dest

lvchange --config 'global {use_lvmetad=0}' -an vgname/lvname

Try to power on the VM on destination

Some questions:

- about overall workflow

- about dd flags, in particular if source disks are thin vs preallocated

Thanks,

Gianluca