Re: is it possible to use LVM AFTER system installation?

[Christian Recktenwald <chris@citecs.de>]

On Sat, Feb 21, 2026 at 06:58:16PM +0100, Frédéric Baldit wrote:
> 
> Hi everybody,
> 
> I'm a debian 12 user, running it on a system which was initially 
> installed without LVM (on a thinkpad laptop)n with classical netinst. My
> system is totally installed on a unique nvme disk, with distinct
> partitions, among which a /home partition for all my personal data.
> 
> I recently installed a second nvme disk (512G capacity). I would like
> to extend my /home ext4 partition (which is now exclusively on
> /dev/nvme0n1p6, 436G) so that I can keep my old data but have
> the possibility to split /home on the initial disk and the second
> recently added disk.
> 
> This seems to be possible with LVM but only when decided at the
> beginning of the installation. Right or wrong?
> 
> Or would it possible to:

create 3 partitions:
1MB for boot loader (grub)
500B for UEFI
rest: LVM PV

Something like:
  VG=vg01
  LVN=lvhome
  DRV=/dev/nvme....
  PART2=/dev/nvme....
  PART3=/dev/nvme....

  SZ=...G # slightly larger (like 1GB) than your current /home

  parted    $DRV mklabel gpt
  # those values are crucial:
  parted -s $DRV unit s mkpart primary      34     2047 set 1 bios_grub on
  parted -s $DRV unit s mkpart primary    2048  1050623 set 2 esp on
  parted -s $DRV unit s mkpart primary 1050624 100%FREE set 3 lvm on
  partprobe $DRV

  mkfs.fat -F32 $PART2
  pvcreate $PART3
  vgcreate $VG $PART3
  lvcreate $VG -n $LVN -L $SZ

  umount /home
  dd if=$OLDHOME of=/dev/$VG/$LVN bs=10M 
  resize2fs /dev/$VG/$LVN
  fsck -f /dev/$VG/$LVN
  $EDITOR /etc/fstab
  mount /home

  live happily ever after...

  cherry on top:
  - mount partition 2 somewhere
    copy the contents of your existing efi boot partition there
    umount partition 2
  - run grub to install on the new drive
  Y? If you ever come across replacing the smaller disk 
  the preparations to get the new disk bootable are already done
  
-- 
Christian Recktenwald      : voice +49 711 601 2091  : Böblinger Strasse 189
chris@citecs.de            : mobil +49 172 711 8104  : D-70199 Stuttgart