I can confirm the warm migration work from OVHcloud Managed vSphere from both vSAN and NFS datastores.
We just need to follow these steps :
- make a snapshot of the VM on vSphere
- import from VMware on XOA with VM stop actions disabled
- once import is finished, remove open-vm-tools on active VM and gracefully stop the OS
- new import from VMware on XOA with VM stop actions disabled -> it detects the VM has already been imported and just sync the delta
- once import is finished, the VM can be started
There are still 2 drawbacks :
- the network interfaces naming differs (ens192/226/etc -> eth0/eth1/eth2) so it needs some reconfiguration
- the network remapping is global so in case a VM has multiple interfaces with different VLANs (ex : pfSense FW), you need to manually set networks before starting the VM
Anyway it works well and make the migration possible for us without waiting for QCOW2 because we don't have >2TB vdisks (we usually add disks and use LVM to grow FS).
Thanks @florent for your help 