Re: [gentoo-user] lvm2 questions

[Philip Webb <purslow@ca.inter.net>]

090604 Maxim Wexler wrote:
> why give the logical volumes any size at all ?
> If they can be expanded at will,
> why not just the let the files fill them up as much as they need ?

That's not how it works: you need to create the LVs with enough space
for your likely needs & LVM then assigns them in its own way to the PVs;
later, if you made an LV too small, you can increase it
(you also have to extend the file system after you've done that,
but of couse don't simply reformat the whole LV);
if you want to decrease an LV -- rather unlikely in real life -- ,
the problem is that you may risk losing data, if that part is dropped:
I would imagine the correct procedure is to copy everything somewhere
-- another LV, another partition, a USB stick -- ,
then delete the LV & recreate it with the smaller size.

When I set up LVM in my newly-built machine in Nov 2007 ,
I tried to estimate what each LV would need based on experience.
Recently, I added a whole new LV & extended another,
but otherwise LVM has worked flawlessly (even SystemRescue recognises it).

-- 
========================,,============================================
SUPPORT     ___________//___,   Philip Webb
ELECTRIC   /] [] [] [] [] []|   Cities Centre, University of Toronto
TRANSIT    `-O----------O---'   purslowatchassdotutorontodotca