LVM is a very cool volume management tool. It can be used for a variety of tasks and this guide explains all the things LVM can do. I also do an example video of combining physical hard drives using LVM.
Acronyms you must know!
PV – Physical Volume
VG – Volume Group
LV – Logical Volume
lvmdiskscan
– system readout of volumes and partitions
pvdisplay
– display detailed info on physical volumes
pvscan
– display disks with physical volumes
pvcreate /dev/sda1
– create a physical volume from sda1
pvchange -x n /dev/sda1
– Disallow using a disk partition
pvresize /dev/sda1
– resize sda1 PV to use all of the partition
pvresize --setphysicalvolumesize 140G /dev/sda1
– resize sda1 to 140g
pvmove /dev/sda1
– can move data out of sda1 to other PVs in VG. Note: Free disk space equivalent to data moved is needed elsewhere.
pvremove /dev/sda1
– delete Physical volume
vgcreate vg1 /dev/sda1 /dev/sdb1
– create a volume group from two drives
vgextend vg1 /dev/sdb1
– add PV to the volume group
vgdisplay vg1
– Display details on a volume group
vgscan
– list volume groups
vgreduce vg1 /dev/sda1
– Removes the drive from vg1
Note: use pvmove /dev/sda1 before removing the drive from vg1
vgchange
– you can activate/deactive and change perameteres
vgremove vg1
– Remove volume group vg1
vgsplit
and vgmerge
can split and merge volume groups
vgrename
– renames a volume group
lvcreate -L 10G vg1
– create a 10 GB logical volume on volume group vg1
lvchange
and lvreduce
are commands that typically aren’t used
lvrename
– rename logical volume
lvremove
– removes a logical volume
lvscan
– shows logical volumes
lvdisplay
– shows details on logical volumes
lvextend -l +100%FREE /dev/vg1/lv1
– One of the most common commands used to extend logical volume lv1 that takes up ALL of the remaining free space on the volume group vg1.
resize2fs /dev/vg1/lv1
– resize the file system to the size of the logical volume lv1.
LVM is fantastic for managing a system, but remember that the more drives you make in a volume group that the likely it is to fail. Instead of having one point of failure you can open yourself up for multiple points when making a large system with multiple drives.
Note: YouTube Video - Hold Ctrl + Left Click to open in new window