[pve-devel] [PATCH qemu-server 15/22] vm start/commandline: activate volumes before config_to_command()

[Fiona Ebner]

Am 17.06.25 um 08:04 schrieb DERUMIER, Alexandre via pve-devel:
>>> With '-blockdev', it is necessary to activate the volumes to
>>> generate
>>> the command line, because it can be necessary to check whether the
>>> volume is a block device or a regular file.
> 
>>> I was thinking about that, but do we have storage with
>>> activate_volume
>>> need to be done for a regular file ?
> 
>>> for lvm plugin for example, we could return always
>>> driver=>host_device.
> 
>>> activate_volume is always done in specific plugin, so the plugin
>>> should
>>> be able to tell if it's a block or file storage
> 
>>> only custom path passthrough in vm configuration need to be checked
>>> if
>>> it's a file or device, but we don't have activate_volume anyway
> 
> 
> But for external snapshot, we need to check the backing file chain
> inside lvm qcow2 volumes, so maybe it's still needed....
> 
> we could use the vm config, but I'm not sure that we can trust it
> safely, in case of snapshot error,  or if an external backup tool like
> veeam do snapshot,
> and if we add snapshot replication like zfs where snapshots are not in
> th vm config

Discussed this yesterday with Fabian off-list a bit more, and we decided
to go with the activate_volumes approach. It's nearly there already,
just need to not deactivate after showcmd.