[pve-devel] [PATCH container] api: restore: keep not backed-up volumes

[Thomas Lamprecht]

Am 05.02.25 um 15:35 schrieb Fiona Ebner:
> Same rationale as in pve-manager commit 5f855ccf ("ui: restore:
> improve warning for restoring container with same ID"): it's
> surprising to (new) users that all owned mount point volumes are
> erased upon container restore, even those that are not currently
> selected for backup. This is different from VM restore, where volumes
> attached at drives not present in the backup will be kept around as
> unused volumes.
> 
> Many users got tripped up by this over the years (e.g. [0][1][2]).
> While the warning added by pve-manager commit 5f855ccf helps, fact is
> that there are still new reports about lost data and thus very bad UX,
> because of this behavior.
> 
> This patch brings the behavior more in line with VM restore. A
> container backup does not contain the detailed information about which
> mount point volumes were included, so rely on the 'backup' flag to
> determine which ones were included and which were not. Note this is
> a bit more careful than VM restore, which only looks whether a volume
> with the same key is included in the backup and does not also consider
> the current 'backup' flag.
> 
> Remove snapshots from the kept volumes, there are no snapshots after
> restore.
> 
> Note that this does not change the fact that mount point volumes
> (according to the configuration contained in the backup) will be
> allocated and thus more space is required in scenarios where some
> volumes are kept.
> 
> The long term plan is to allow selecting actions for volumes
> individually. For now, use a safer default.
> 
> [0]: https://bugzilla.proxmox.com/show_bug.cgi?id=3783
> [1]: https://forum.proxmox.com/threads/109707/post-745415
> [2]: https://forum.proxmox.com/threads/111760/post-482045
> 
> Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
> ---
> 
> Since other users might rely on the current removal, we probably want
> to wait until either the next point release with this or even until
> PVE 9.
> 


Another option might be to make this opt-out in the UI, i.e. not
per volume (can be done later) but for the whole restore.

btw. pve-manager commit 5f855ccf would need to be reverted along
side this to avoid making UX even more confusing.