[fulafel]

This is not the case, as like I said you can shrink either of those filesystems and its container and use the freed space for this.

(Also I think lvm doesn't need the volume blocks to be contiguous on the physical volume. So you might have N free space after volume a and M after volume b, and lvm would let you create a new N+M sized volume.)

[Am4TIfIsER0ppos]

So when I have root and home mounted because I am using the computer can I shrink them? No because they are mounted.

[fulafel]

The easiest way to resize the root partition is probably to boot from eg Ubuntu live/install USB stick. The home partition you can unmount (but not while non root user sessions are using it).

[Am4TIfIsER0ppos]

> reboot into another OS

As I said: garbage for snapshots

[fulafel]

You need to do it only once (if you didn't do it at install time), not every snapshot.