i do have the knowledge about the possible of having more cpu overhead than the improvement in transfer speed.. but when it comes to space saving, i think it does worth it. i have been using btrfs compression on opensuse for quite a while. the space saving is amazing. with compression enabled, the space usage is half the normal size.
the only concern im having about getting this to be done is the kernel. does the kernel we are using support btrfs compression at the first place(mblaster?)? i do not have the technical knowledge of how to get this done. hope someone could turn this idea to a reality.