Why use LVM when ordinary partitions work?

The short answer

For a small, fixed-layout system, ordinary partitions may be all you need. LVM earns its keep when storage needs to change. It lets you allocate space from a shared pool, extend logical volumes, and use features such as snapshots and thin provisioning.

It is a tool for flexibility, not a mandatory ingredient in every Linux installation.

What is wrong with partitions?

Nothing. A filesystem on a normal partition is easy to understand, inspect and recover. If you know your disk layout and do not expect it to change, simplicity is a feature. The challenge comes when one filesystem is nearly full while another has plenty of unused capacity, or when you add another disk and want to grow an existing volume.

PV, VG and LV in plain English

LVM separates the underlying storage from the logical volumes used by filesystems.

disk or partition → Physical Volume (PV)
PV(s)             → Volume Group (VG)
VG free space     → Logical Volume (LV)
LV                → Filesystem → Mount point

Think of a volume group as a pool of storage and logical volumes as allocations from that pool. A logical volume can be expanded if the group has free extents; the filesystem may also need to be grown separately.

Where LVM is genuinely useful

Common uses include growing filesystems without repartitioning, adding physical storage to a volume group, creating logical volumes for different workloads, and taking snapshots for short-lived consistency workflows. LVM can also support thin provisioning, though that introduces its own monitoring responsibilities.

When I would keep it simple

LVM adds an abstraction layer and another set of tools to learn. It does not automatically provide redundancy, backup, or protection from disk failure. Shrinking is much more delicate than growing and depends on the filesystem: for example, XFS cannot be shrunk. Plan backups before modifying any storage layout.

For a tiny VM with one filesystem and predictable growth, plain partitions may be the better answer.

Explore safely

Start by inspecting an existing LVM system. These commands do not change the disk layout:

lsblk -f
sudo pvs
sudo vgs
sudo lvs -a -o +devices

If the machine is not using LVM, the last three commands may show no configured volumes. Build and destroy experimental volume groups only in a disposable VM with dedicated test disks.