// learn · linux · rhcsa · 8 min

LVM stacking.

Logical Volume Manager turns physical disks into pools you can carve, grow, snapshot, and migrate without downtime. Build the stack layer by layer; then extend live and snapshot. Maps to the RH134 storage objectives.

LVM (Logical Volume Manager) explained with animations. Physical volumes, volume groups, logical volumes, filesystems, extension, and snapshots. Covers the RHCSA EX200 exam objectives on LVM storage.
// LVM stacking

LVM is a layer between your disks and your filesystem. The payoff: combine multiple disks into one pool, carve flexible "virtual partitions" out of it, grow them online, and snapshot for backup. Build the stack one layer at a time.

// before you start
you should know
  • ·Mounting a filesystem (mount, /etc/fstab)
  • ·Reading block devices with lsblk and df
  • ·Comfortable as root or with sudo
by the end you'll

Build a Volume Group, carve a Logical Volume out of it, format/mount it, then extend it online and snapshot it for backup — explaining each layer.

pace: 8 minutes

lvm stack — step 1 / 7 · bare disks
💽 /dev/sda20 GiB💽 /dev/sdb20 GiB💽 /dev/sdc20 GiBDISK

Before LVM — bare disks

Without LVM, you'd partition each disk with fdisk/parted and put a filesystem directly on the partition. Need more space? Back up, repartition, restore — usually with downtime.

// commands at this step
$lsblk
// key insight

The LVM commands all start with the layer they operate on: pv* for physical volumes, vg* for volume groups, lv* for logical volumes. Master the naming and the rest follows: pvs / pvdisplay, vgs / vgdisplay / vgextend, lvs / lvdisplay / lvextend / lvreduce / lvremove.

// exam-ready · the full LVM toolkit
$pvs / pvdisplay
$pvcreate /dev/sdX1
$vgs / vgdisplay
$vgcreate vg_data /dev/sdX1 /dev/sdY1
$vgextend vg_data /dev/sdZ1
$lvs / lvdisplay
$lvcreate -L 10G -n NAME vg_data
$lvcreate -l 100%FREE -n NAME vg_data
$lvextend -L +5G --resizefs /dev/vg/NAME
$lvreduce -L -2G --resizefs /dev/vg/NAME
$lvcreate -s -L 2G -n NAME_snap /dev/vg/NAME
$lvremove /dev/vg/NAME
$vgrename / lvrename
$pvmove /dev/sdold
// check yourself
4 quick questions
Q1

Which LVM layer pools multiple physical volumes into a single space?

Q2

Your /var/www LV is full. Disk has free space. One-line fix?

Q3

You want to take a consistent backup of /var/www without stopping writes. What's the LVM move?

Q4

Which file system can NOT be shrunk online (or at all without unusual tools)?

These aren't graded — they're just for active recall, which is what actually makes the lesson stick.

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