This short HOWTO shows how to create and manage LVM partitions.

LVM allows you to group multiple physical partitions together, and to then divide that space up in to multiple logical partitions. Space can be moved between logical partitions as required.

In this example we use a single partition (/dev/mapper/crypthome) which has been created using DM-CRYPT on top of MD software RAID, but you could just as easily put LVM directly on top of RAID (example: /dev/md0), or directly on a physical partition (example: /dev/sda1).

To install the LVM2 user-space tools:

aptitude install lvm2

To prepare a physical volume (your target partition) for LVM:

pvcreate /dev/mapper/crypthome          # (or /dev/sda or /dev/md0)

To list physical volumes used for LVM:

pvdisplay

To move data from one physical volume to another:

pvmove /dev/crypthome /dev/someotherpartition

To remove a physical volume:

pvremove /dev/mapper/crypthome

To create a volume group (lvmhome) from a physical volume (/dev/mapper/crypthome):

vgcreate lvmhome /dev/mapper/crypthome

To show the status of volume groups:

vgscan
vgdisplay

To rename a volume group:

vgrename lvmhome lvmhome2

To delete a volume group:

vgremove lvmhome

To add another volume to an existing volume group:

vgextend lvmhome /dev/yournewpartition

To remove a volume from a volume group:

vgreduce lvmhome /dev/youroldpartition

To create a logical volume named home in the volume group lvmhome:

lvcreate --name home --size 100G lvmhome

List and display the status of logical volumes:

lvscan
lvdisplay

To rename a logical volume:

lvrename data home newname

To delete a logical volume:

lvremove /dev/data/home

To format and mount a logical volume:

mkfs.ext3 /dev/lvmhome/home
mount /dev/lvmhome/home /home
df -h

To automatically mount a logical volume at boot list it in /etc/fstab:

/dev/lvmhome/home	/home	ext3	rw,noatime	0	0

To grow a logical volume:

umount /home
lvextend -L200G /dev/lvmhome/home
e2fsck -f /dev/lvmhome/home
resize2fs /dev/lvmhome/home 200G
mount /dev/lvmhome/home /home
df -h

To shrink a logical volume:

umount /home
e2fsck -f /dev/lvmhome/home
resize2fs /dev/lvmhome/home 50G
lvreduce -L5G /dev/lvmhome/home
mount /dev/lvmhome/home /home
df -h