[breezy install] LVM option?

[David Hart]

On Mon, Dec 05, 2005 at 01:15:48AM -0500, David Abrahams wrote:
> Is the LVM partitioning option of the Breezy installer known to
> actually work?  I have read all about LVM and I understand
> partitioning (having done many prior Linux installs), but I couldn't
> get the LVM options to do anything sensible.  Well, that's not quite
> true: I got the thing to put two physical partitions on my 30GB disk,
> one a 255MB /boot partition and the remaining space allocated to /,
> and two logical volumes soaking up the physical space on /, the
> smaller of which got allocated to /swap.  That's the default you get
> when you tell it to erase your 30GB disk and use LVM.

I would expect an auto partition on LVM to create nothing more than
/boot as a primary partition (because grub can't read LVM) possibly
another for swap (but it could, I think go into the LVM) and the rest
for / in the LVM, which, from what I can make out, is what it has done.
An auto partitioner is not able to know how you want your disk
partitioned beyond assuming a basic setup.

The two Breezy boxes that I have LVM on were originally partitioned for
Gentoo two or more years ago and I configured it manually in the Ubuntu
installer.

Here's 'fdisk -l' on the laptop I'm using now:
  Disk /dev/hda: 60.0 GB, 60011642880 bytes
  255 heads, 63 sectors/track, 7296 cylinders
  Units = cylinders of 16065 * 512 = 8225280 bytes
  
     Device Boot      Start         End      Blocks   Id  System
  /dev/hda1               1           6       48163+  83  Linux
  /dev/hda2               7          12       48195   83  Linux
  /dev/hda3              13         134      979965   82  Linux swap /
  Solaris
  /dev/hda4             135        7296    57528765    5  Extended
  /dev/hda5             135         170      289138+  83  Linux
  /dev/hda6             171         206      289138+  83  Linux
  /dev/hda7             207         692     3903763+  83  Linux
  /dev/hda8             693        1178     3903763+  83  Linux
  /dev/hda9            1179        2394     9767488+  8e  Linux LVM
  /dev/hda10           2395        3610     9767488+  8e  Linux LVM
  /dev/hda11           3611        4826     9767488+  8e  Linux LVM
  /dev/hda12           4827        6042     9767488+  8e  Linux LVM
  /dev/hda13           6043        7296    10072723+  8e  Linux LVM

I leave space for two /boot (hda1,hda2), two / (hda5,hda6) so that if
necessary, I can do a fresh install rather than dist-upgrade without
disturbing my previous install.  hda7,hda8 are a bit of spare space for
testing other distros.  Everything else goes in the LVM.

Here's 'lvscan':

  ACTIVE            '/dev/vg/wartyhome' [1.00 GB] inherit
  ACTIVE            '/dev/vg/stuff' [25.00 GB] inherit
  ACTIVE            '/dev/vg/hoarytmp' [1.00 GB] inherit
  ACTIVE            '/dev/vg/hoaryusr' [4.00 GB] inherit
  ACTIVE            '/dev/vg/hoarylocal' [500.00 MB] inherit
  ACTIVE            '/dev/vg/hoaryvar' [1.00 GB] inherit
  ACTIVE            '/dev/vg/hoaryhome' [1.00 GB] inherit
  ACTIVE            '/dev/vg/hometmp' [1.00 GB] inherit
  ACTIVE            '/dev/vg/tmp' [1.00 GB] inherit
  ACTIVE            '/dev/vg/usr' [4.00 GB] inherit
  ACTIVE            '/dev/vg/local' [500.00 MB] inherit
  ACTIVE            '/dev/vg/var' [1.00 GB] inherit
  ACTIVE            '/dev/vg/homecur' [2.00 GB] inherit
  ACTIVE            '/dev/vg/home' [2.00 GB] inherit

These were all originally setup from the installer, not manually.
(and I _still_ haven't tidied up some partitions since Warty :-O)
 
> However, I was unable to add logical volumes or modify the volume
> group: the partitioner would tell me there was no physical volume to
> operate on (!)  I'm pretty sure I want more than just two top level
> logical volumes.  Even though the installer does nothing smart about
> that by default, everything I've read makes plausible arguments that I
> ought to be separating /var, /home, /tmp, etc., from one another.

You first need to decide on and setup your physical partitions and
allocate the rest to type LVM (either one big LVM volume or split over
several partitions as I've done) all from the main manual installer
screen.  Once done, you go to the LVM option at the top (I'm describing
this from memory) and it will write the partitions to disk.  From there you
should be in a menu which will let you create volume groups and logical
volumes to go in them.  I'm only using one volume group at the moment
but you can set it up however you want.

Once you have your logical volumes created you should find yourself at
the main manual installer screen again where you can allocate the logical
volumes to the parts of the filesystem that you want.
 
> I'm starting to get the feeling that this part of the installer
> doesn't really work and I should expect to have to use pvcreate,
> vgcreate, etc., from the command line, in order to really manage the
> LVM configuration.  But I have no idea whether this can actually work.

It definitely works (well, at least it has for me) but it's not the
most intuitive of interfaces and threw me a bit the first time I
used it.
 
> Can anyone help?  TIA,

HTH

-- 
David Hart <ubuntu at tonix.org>