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

[Dale]

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

Dale

:-)  :-)