Re: [gentoo-user] LVM for data drives but not the OS

[Joost Roeleveld]

On Saturday 09 April 2011 06:43:25 Dale wrote:
> Alan McKinnon wrote:
> > Apparently, though unproven, at 12:48 on Saturday 09 April 2011, Dale
> > did
> > opine thusly:
> > Yes.
> >
> > PVs, VGs, LVs all have a concept of extend|resize|reduce. What that
> > means
> > depends on what you are working with, but they all make the thing bigger
> > or smaller.
> >
> > For a PV it means the underlying device's size changed, so the PV must
> > change to match. Take a 500G drive, create 1 partition on it of 100G
> > and make it a PV. Now enlarge the partition to 200G, you must extend
> > the PV to match.
> >
> > A VG isn't a single thing, it's a collection of things. Extending it
> > means to add more PVs, reducing it means to take PVs out of the VG.
> > Hopefully you will always remember to migrate the data off a PV before
> > removing it from a VG :-)
> >
> > Extend/Reduce an LV means to make the device larger/smaller. It is
> > exactly the same thing as changing a partition size using fdisk.
> > Obviously, you need to tweak the filesystem at the same time
>
> So, when I get me a new drive, I use pvcreate to get it ready for LVM,
> then use vgextend to add it to the VG, then it is available for whatever
> LV I want to extend or to make a new LV?
>
> I think I am catching on here.  It was just difficult for me to grasp
> how things are layered for some reason.  Some of the pictures I found
> helped a good bit tho.  Just helped me picture what the commands are
> doing exactly.
>
> I did learn the hard way to resize the file system tho.  I forgot that
> earlier.  Sort of had me scratching my head for a bit.  lol

That's an easy one to miss :)

You do seem to be catching on quick on this.

--
Joost