(new thread to separate things a bit more) Today I took the effort to completely re-install one of my two older thinkpads.
booted via USB (sysresccd) because the X220 has no optical drive, backed up the contents of / and the encrypted /home to an external drive and started up gdisk to reorder the partitions. There were: sda1 /boot/efi sda2 swap (encrypted) sda3 /root (the old ext4) sda4 encrypted /home sda5 /root (the new btrfs) Wasting the ~25GB of sda3 was not acceptable ;-) and adding that device to the new btrfs-pool somehow lead to flaky results with grub2-mkconfig It seems to not detect or interpret correctly the fact that there are 2 physical devices in there and then the "linux ..." line for grub.cfg gets messed up, at least for me here. Played around with that and then decided to redo all that from scratch. Removed sda[345] and did: sda1 /boot/efi sda2 swap (encrypted) sda3 /root (new bigger btrfs) sda4 encrypted /home (with btrfs inside) copied back my stuff, chrooted and re-fiddled my grub2/EFI-setup, that took me a bit but now it works great. - And even better(?): no more initrd included now! grub2-mkconfig somehow decides not to need the initrds generated by Canek's kerninst and it boots up fine so far. I will check if I should keep it that way or somehow enforce the usage of the initrd. opinions? - I looked if I can get rid of lvm2-pkg completely but AFAI understand I need that for cryptsetup, right? So I masked the lvm2-activation-services ... they don't do anything now at boot time ... a bit more speed (tiny) and less complexity somehow. - So quite a learning curve these days :-) Thanks for all the help and infos on this list, btw ... Stefan