Metaphorically, volume groups can be seen as storage buckets : they are a pool of different physical volumes that can be used to extend existing logical volumes or to create new ones. Right over physical volumes, volumes group can be seen as multiple physical volumes grouped together to form one single volume. Physical volumes are named in the same way than physical partitions : /dev/sda1 for the first partition of your first hard drive, /dev/sdb1 for the first partition of your second drive and so on. When system administrators refer to “physical volumes”, they often mean the actual physical device storing data on our system. When using LVM, physical volumes are meant to represent partitions already existing on your hard drives.
In this tutorial, we are going to learn about LVM and how you can easily implement them on your system.īetween partitions and filesystems, you have three additional layers : physical volumes, volume groups and logical volumes.
LVM, short for Logical Volume Management, comes as a set of tools that allows you to extend, shrink existing volumes as well as replacing existing disks while the system is running. Luckily for you, there is a tool, or an abstraction that you can use on Linux to manage storages : LVM. Similarly, it is quite hard to extend a filesystem if you add a new disk to your system : you would have to move data from one disk to another, sometimes leading to data loss. However, those three layers are usually tighly coupled : it can be quite hard to shrink existing partitions to create a new one. Traditional storage is usually made of three different layers : the physical disk (whether it is a HDD or a SSD), the logical partitions created on it and the filesystem formatted on the partition. On Linux, it can be quite hard to manage storage and filesystems and it often needs a lot of different commands to move data.
0 kommentar(er)
