LVM (Logical Volume Manager) is a device mapper framework that provides logical volume management for the Linux kernel. It abstracts physical storage devices, allowing administrators to create virtual partitions that can span across multiple physical disks and be resized dynamically.
The structure consists of Physical Volumes (PV), which are initialized disks or partitions; Volume Groups (VG), which pool the capacity of PVs; and Logical Volumes (LV), which are the usable block devices formatted with a file system.
How it works
LVM divides storage into fixed-size chunks called Physical Extents (PE). By mapping these extents to logical volumes, the system gains flexibility. If a volume runs out of space, an administrator can add a new disk to the VG and expand the LV using lvextend without unmounting the file system.
This technology is standard for enterprise Linux deployments. It supports advanced features like snapshots for point-in-time backups and thin provisioning. A key advantage is the ability to migrate data from a failing drive to a healthy one using pvmove while the system remains operational.