Thanks for the feedback. I came up with the following "LUKS on LVM" scheme:
NAME SIZE TYPE MOUNTPOINT FSTYPE /dev/sda 111,8G disk |-/dev/sda1 32M part /boot/efi vfat `-/dev/sda2 111,7G part /dev/sdb 298,1G disk /dev/sdc 238,5G disk /dev/vg0 350,2G lvm |-/dev/vg0/lvol1 150,2G lvm / btrfs `-/dev/vg0/lvol2 200G lvm `-/dev/mapper/home 200G crypt /home btrfs /dev/vg1 298,1G lvm `-/dev/vg1/lvol1 298,1G lvm `-/dev/mapper/storage 298,1G crypt /mnt/storage btrfs It is important that /var is not located on a separate partition in order to utilize the benefits of copy-on-write for installing packages. sys-kernel/installkernel[grub,systemd,ugrd] will be used to generate and install initramfs. And I'll look into my OpenSMTPd and Dovecot configuration for options. So, planning is done, time for backing my data up and doing actual disk manipulation.
