LVM2

LVM2, or Linux Logical Volume Manager version 2, is a device-mapper based storage management subsystem for Linux. It provides a flexible layer of indirection between physical storage and the filesystems that use it, enabling dynamic resizing, snapshots, and more advanced layouts than traditional partitioning. LVM2 supersedes the original LVM1 implementation and is widely used across Linux distributions and data centers.

LVM2 consists of kernel-space components built on the Linux device-mapper framework and a set of user-space tools that manage storage. The user-space tools manage physical volumes, volume groups, and logical volumes, while the kernel component implements the device-mapper targets that expose the logical volumes to the system. This separation allows complex storage arrangements to be manipulated from user space while the kernel provides a unified interface for I/O.

Key concepts in LVM2 include physical volumes (PVs), which are disks or partitions prepared for LVM; volume groups (VGs), which are pools of storage created from one or more PVs; and logical volumes (LVs), which are virtual partitions carved from a VG and presented to the system as block devices. LVM2 also supports advanced features such as snapshots, thin provisioning via thin pools and thin volumes, and striping or mirroring within a VG to provide redundancy or performance benefits.

Common management tasks include creating PVs, assembling VGs, creating and resizing LVs, and taking or removing snapshots. LVM2 maintains metadata about the storage layout on the PVs and offers metadata backup and restoration capabilities to aid in recovery. It remains a central tool for flexible storage management in Linux environments.