Re: [RFC storage, qemu-server] offload full/live clone to storage backend

[Fiona Ebner <f.ebner@proxmox.com>]

Am 08.07.26 um 10:43 AM schrieb Fabian Grünbichler:
> On July 8, 2026 10:17 am, Fiona Ebner wrote:
>>>>
>>>> Out of scope
>>>> ------------
>>>> - Cross-storage and format-converting clones (inherently
>>>>   host-mediated).
>>>
>>> agreed. cross-storage could potentially be a follow-up, and we might
>>> want to account for it in the copy_image signature/parameters?
>>
>> I think we'd need an abstraction similar to
>> volume_{export,import}{,formats} so that plugins don't deal with
>> internal information from other plugins?
> 
> I guess a valid baseline assumption is that offloaded copies can only
> ever occur between two storage instances of the same plugin type? how
> the plugin then decides that the two instances can be used for copying
> or not is up to the plugin (e.g., zfs can send/recv locally, a storage
> appliance might have a copy feature between namespaces, but not
> between storage pools or appliances, ..).
> 
> volume_export/import can be split like that because we lower to some
> transport format, but that is not possible for offloading, which is
> opaque from PVE's point of view..

Different storage types based on the same underlying technology (e.g.
ZFS) could still do it. That said, I don't mind not designing for this
but just for offloading between storages of the same type.