A Beginner’s Guide to LVM in Linux
TL;DR: Learn the basics of LVM (Logical Volume Manager) in Linux to efficiently manage disk space with flexible, dynamic storage options.
The Logical Volume Manager (LVM) is a powerful storage management tool in Linux that abstracts physical storage into virtual disks. LVM allows you to easily resize logical volumes, making it a flexible alternative to traditional partitioning.
What is LVM in Linux?
LVM, introduced by Red Hat in 2001, is now a standard feature in many Linux distributions. It allows you to manage physical storage as virtual disks (logical volumes) that can be resized and managed with ease. LVM works similarly to RAID by pooling multiple physical disks into virtual storage devices.
Components of LVM
- Physical Volume (PV): Actual storage devices like hard drives.
- Volume Group (VG): A pool of multiple PVs.
- Logical Volume (LV): Virtual partitions within a VG.
- Physical Extent (PE): Smallest storage unit in a PV.
- Logical Extent (LE): Similar to PEs, but within LVs.
- Metadata: Describes the configuration of PVs, VGs, and LVs.
Installing LVM
To install LVM on Ubuntu or Debian-based systems:
sudo apt update
sudo apt install lvm2
Creating Partitions
Using lsblk, check your disk details. For partitioning, use the parted command:
sudo parted /dev/sdb
Commands inside parted:
mklabel gpt
unit GB
mkpart primary 0 8GB
mkpart primary 8GB 16GB
print
quit
Creating Physical Volumes (PV)
To create physical volumes on your partitions:
sudo pvcreate /dev/sdb1
sudo pvcreate /dev/sdb2
List all PVs:
sudo pvs
Creating a Volume Group (VG)
Create a volume group named foss_vg:
sudo vgcreate foss_vg /dev/sdb1 /dev/sdb2
List volume groups:
sudo vgs
To extend a VG with a new drive:
sudo vgextend foss_vg /dev/sdb3
Creating Logical Volumes (LV)
Create logical volumes:
sudo lvcreate -L 2048 -n foss_lv_01 foss_vg
sudo lvcreate -L 4096 -n foss_lv_02 foss_vg
View LVs:
sudo lvdisplay
Creating a Filesystem on Logical Volumes
Format the LV with an ext4 filesystem:
sudo mkfs.ext4 -m 0 /dev/foss_vg/foss_lv_01
Mount the filesystem:
sudo mount /dev/foss_vg/foss_lv_01 /mnt
Extend a Logical Volume
To extend the LV size:
sudo lvextend -L +1200 /dev/foss_vg/foss_lv_01
sudo resize2fs /dev/foss_vg/foss_lv_01
Remove a Logical Volume
To delete an LV:
sudo lvremove /dev/foss_vg/foss_lv_01
Auto-Mounting LVs on Boot
Edit /etc/fstab to automatically mount the LV at boot:
sudo nano /etc/fstab
Add the following line:
/dev/foss_vg/foss_lv_01 /mnt ext4 defaults 0 2
Reload systemd:
sudo systemctl daemon-reload
Conclusion
LVM simplifies storage management in Linux by providing flexible and dynamic disk management capabilities. It allows for easy resizing and management of storage, making it a valuable tool for system administrators and power users alike.