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

Christian Recktenwald
2026-02-21T20:38:03Z

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