[pve-devel] [PATCH-SERIES v6 pve-storage/qemu-server/pve-qemu] add external qcow2 snapshot support

[Fiona Ebner]

Am 05.06.25 um 16:08 schrieb DERUMIER, Alexandre:
> Am 03.06.25 um 09:55 schrieb Alexandre Derumier via pve-devel:
>> This new patch series enable blockdev for qemu machine > 10.0 to
>> avoid breaking efidisk and maybe
>> potential migrations bug
> 
>>> Did you see any actual issues with migration or mirroring the EFI
>>> disk
>>> now or is this just a gut feeling?
> 
> I don't have tested it to be honest (because don't use efi in
> production, and I really don't known how to verify that it's working
> fine after a migration+ also the size param) , so it was more by
> security
> 
> but as it's attached to -machine... directly instead -drive, I really
> don't known.  and they was also the version gate for old machine
> version without raw support.
> 
> We also need to handle migration+storage motion for local dirve between
> pve8->pve9, and
> I don't have tested if pve8 can still use drive-mirror to pve9 nbd
> blockdev.
> 
> 
> I only have tested live vm migration with shared storage between pve8
> to pve9 without efi,
> and the switch from drive to blockdev was working fine.

I am inclined to go with version guarding too. I'm doubtful we can cover
all edge cases and all defaults even if we are very careful. There are
just too many possible options and combinations for drives. It's likely
already required for setting the 'write-cache' option on the front-end
drive device, since we didn't do that before. Maybe that won't change
the migration stream either, but it's better to be safe than sorry.