LVM can be extremely helpful in dynamic environments, when disks and partitions are often moved or resized. The option to setup LVM is presented during the installation of any modern Linux distribution, should you use it? The answer depends on the actual use case. Many users have reported significant performance issues when creating snapshots, which limits their use in a production system.įinally, modern file system like zfs or btrfs support most of the advanced features of LVM (online resizing, snapshotting), without the need to add another layer. Since most Linux file systems don’t support online resizing, a period of downtime is needed. While the ability to resize logical volumes is very useful, the file systems installed on them must be resized separately.

While the overhead of LVM is usually small, any decrease in performance can be critical on busy systems. The main disadvantage of LVM is that it adds another layer to the storage system. In addition, LVM allows the creation of instant logical volume snapshots while the operating system is running and supports advanced encryption features. Logical volumes can also be resized dynamically, so you can start for example with a small partition and configure it to expand as data is written on it.Īny number of disks and partitions can be unified into a big one, or a single physical disk can be quickly split into many partitions of any size. The biggest advantage of LVM is that both logical and physical volumes can be created, deleted and resized online, without any restarts. PEs can be added and removed from volumes on the fly and are the core concept that powers LVM. These have a default size of 4 MB, must be contiguous and are the smallest units that can be allocated. LVM splits physical volumes into small chunks names Physical extents (PE). A logical volume doesn’t have to be contiguous, it can stretch on multiple disks, can be easily migrated and you can assign it a name instead of a number for easier identification. Unlike traditional disk partitions, the logical volumes are very flexible because they are abstracted in their volume group.

These are the actual partitions that can be formatted with various file systems and used by the operating system. Volume groups can be quickly resized by adding or removing physical volumes.įrom a volume group, the Logical volumes (LV) are created.

They create a unified storage space, combining the capacity of all underlying devices. The physical volumes are combined into Volume groups (VG), which serve as storage pools. These can be any kind of available storage devices like actual discs (hard drives, SSDs, etc), RAID arrays, MBR and GPT partitions or various other block device nodes. The basic building blocks of the system are Physical volumes (PV). We will discuss in this article what are the advantages and disadvantages of LVM, as well as some potential use cases. However, there are also scenarios when it is pointless to use it or there are better options available. LVM provides more flexibility when compared with traditional partitions, which can be extremely useful in many cases. While many people confuse LVM with the file system, it actually works on a separate layer in order to create a virtual partitioning scheme on top of the actual disk layout. LVM, or the Logical Volume Manager, is a Linux volume partitioning solution that has been around for some time and provides a number of advanced features.

Ubuntu volume manager