Dear Maintainer,

Please allow the use of existing Physical / Logical Volumes and Volume Groups when using expert_recipe similar to normal partitions.

This allows the preseeding of installations where an existing LVM Volume contains Data that should be kept intact, e.g. for multi boot setups, or a seperate /, /var, /home on LVM where only / should be erased.
Currently this is not possible, as auto-lvm wipes any existing PVs, VGs, LVs unconditionally, even if the expert_recipe results in them being recreated in the exact same way immediately.

This was already requested / asked a few times:

https://lists.debian.org/debian-boot/2015/05/msg00339.html

https://lists.debian.org/debian-boot/2013/08/msg00275.html