[PVE-User] vzdump: backup kvm lvm2 vm. Full backup ok, differential ?

[dea]

> > vzdump after LVM2 snapshot create a "dd" image of KVM container, perfect
> > for full backup, but is there a solution for differential backup ?
> 
> No, vzdump is only for full backups.

OK ! Is there a special version of dd (or other software) can dump a LVM
container (after snapshot) differentially compared to a previous full dump ?

Theoretically is not complicated .. together with the full dump the program
can create an hash file (an hash of each block), the full dump can be moved to
other storage, the differential dump can be create using the (small) hash file.