Introduction to Logical Volume Manager

Disk management has always been one of the most important tasks that system administrators perform. Historically, this would involve a lot of pre-planning and precision. Logical Volume Manager (LVM) doesn't completely alleviate these concerns; however, it is a bit more forgiving if you make an error in your calculations or just decide to do something different in the future. LVM was written in 1998 and has been a powerful ally for sysadmins since that time.

So, what advantages does it offer? Well, the big thing for most people is that LVM allows for dynamic resizing. This means that a sysadmin can allocate more space for a volume on the fly. In the past, you would have to unmount the volume in order to change its properties; however, LVM only requires this when downsizing.

LVM architecture

LVM consists of three key pieces. At the heart of LVM, your physical volumes (PV) will act as your starting point. These are physical "block devices" that must be initialized for LVM use, using the pvcreate command. Once you have your physical volumes, we can combine those into a single volume group (VG) using the vgcreate command. The volume group takes on the full capacity of the combined devices and is seen as a single storage device. From here, we can create various types of logical volumes (LV) to suit our needs using the lvcreate command.

What's next?

If LVM sounds like something that you are interested in or is something you are looking to get started with, I have written a few articles to discuss the basics and configuration of each piece of the LVM puzzle. You will find step by step instructions with examples and even some light troubleshooting for each of the necessary commands! So dive right in and let us help you learn something new today!

• How to create a physical volume in Linux using LVM
• How to create a volume group in Linux with LVM
• Creating logical volumes in Linux with LVM

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