Planned to go the btrfs-only route, but as there is no way to bring lzo compression and syslinux together, I added a ext2 boot partition, the EF02 partition is there for future experimantion with grub2 only.
ssd disk layout: GPT sda1 -> 2 MiB -> Bios boot -> EF02 sda2 -> 200 MiB -> Linux FS -> 8300 sda3 -> REST -> Linux FS -> 8300 sda4 -> 2 GIB -> Swap -> 8200 sgdisk -A 2:set:2 /dev/sda # SET LEGACY BOOT FLAG mkfs.ext2 -L boot /dev/sda2 mkfs.btrfs -L b-root /dev/sda3 mkfs.swap -L swap /dev/sda4 mkdir /b-root && mount -o defaults,noatime,discard,ssd,compress=lzo /dev/sda3 /b-root btrfs subvolume create /b-root/__active btrfs subvolume create /b-root/__active/home btrfs subvolume create /b-root/__active/usr btrfs subvolume create /b-root/__active/var chmod -R 755 /b-root/__active # BTRFS CREATES SUBVOLUMES WITH 0700 umount /b-root # not sure about it mount -o defaults,noatime,discard,ssd,compress=lzo,subvol=__access /dev/sda3 /mnt mkdir /mnt/boot mount /dev/sda2 /mnt/boot setup # INSTALL SLACKWARE chroot /mnt add following line to fstab: /dev/sda2 /boot ext2 defaults 0 0 /dev/sda3 / btrfs defaults,ssd,discard,noatime,compress=lzo,subvol=__active 0 0 mkdir /boot/extlinux extlinux --install /boot/extlinux # INSTALL BOOTLOADER cat /usr/share/syslinux/gptmbr.bin > /dev/sda # WRITE BOOTLOADER TO MBR vim /boot/extlinux/extlinux.conf: PROMPT 0 TIMEOUT 0 DEFAULT slacky LABEL slacky KERNEL /boot/vmlinuz-huge-3.2.29 APPEND root=/dev/sda2 rootflags=subvol=__active,compress=lzo ro elevator=noop