Making a Linux Logical Volume

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Start:

Make sure that your disk has a clean partition that you are able to convert into a usable disk, aka allow the LVM (logical volume manager) to use your storage.

Option 1. Using entire disk:

First, you want to delete all partitions and previous data that is on the drive, you CANNOT directly convert a drive into a logical volume while keeping the data, as it using formatting to allow for drive expansion.

Delete partitions

We will use the fdisk tool that comes with most linux distributions to modify your disk.

First, list all your drives to make sure that you are selecting the right drive:

sudo fdisk -l

Then, its time to wipe the disk of all partitions (replace sdXX with the drive you choose):

sudo fdisk /dev/sdXX

This will open the fdisk menu, you should see Command (m for help): at the bottom of the terminal

Quick note

If you got a red error saying that the drive is running, MAKE SURE TO UNMOUNT THE DEVICE. If you cannot unmount it conventionally, run:

sudo umount -l /dev/sdXX

(if you are not sure where the mount is located, use gnome-disks)

Run these commands (the letters, also one at a time):

# Deletes your partition (might need to run multiple times)
Command (m for help): d

# Creates a new clean partition
Command (m for help): n
# Press enter through all of these
Partition Number: (1-128, default 1): <Press Enter>
First Sector (2048-XXXXX, default 2048): <Press Enter>
Last Sector, +/-sectors or +/-size{K,M,G,T,P} (2048-XXXXX, default XXXXX): <Press Enter>

# Edits the kind of partition that it will be, in this case we want 8e (LVM)
Command (m for help): t
Selected Partition: 1
Partition type or alias (type L to list all): 8e

# Write this to the disk so that it will be saved
Command (m for help): w

Option 2. Extend Partitions WORKING ON

If you want to use unused parts of your primary/drive or want to just use extra space on other drives without compromising their data, you can instead use that extra space as logical volume styled partitions

# Deletes your partition (might need to run multiple times)
Command (m for help): d

# Creates a new clean partition
Command (m for help): n
# Press enter through all of these
Partition Number: (1-128, default 1): <Press Enter>
First Sector (2048-XXXXX, default 2048): <Press Enter>
Last Sector, +/-sectors or +/-size{K,M,G,T,P} (2048-XXXXX, default XXXXX): <Press Enter>

# Edits the kind of partition that it will be, in this case we want 8e (LVM)
Command (m for help): t
Selected Partition: 1
Partition type or alias (type L to list all): 8e

# Write this to the disk so that it will be saved
Command (m for help): w

You now have a partitioned disk that can be used for LVM purposes

Creating a Logical Volume

Now that you have a free partition that can be used for a LVM, you need to make it into a physical drive

Creating a physical drive

sudo pvcreate /dev/sdXX

To verify that it worked, run:

sudo pvdisplay

Creating the volume group

This will make a volume group (vg) named vg-data, you can use a different name instead:

sudo vgcreate vg-data /dev/sdXX

# Check to see that it worked:
sudo vgs

Creating the logical volume

Will create the logical volume that will soon be mounted to your system so that you can use it, you can replace lv-data with another name, just remember that vg-data is the right name.

# Will use all of the free space in the volume group to add to the logical volume
sudo lvcreate --name lv-data -l 100%FREE vg-data

You now have a logical volume! This can be added to easily so that you can expand your storage, even if you have processes running on the logical volume (really nice).

Adding LV to file-system

Now that you have a logical volume, you’ll notice that you can’t save any data to it quite yet, in order to do that you need to make/add a file-system

Option 1. Making your LV into a file-system

If you have not already made a accessible logical volume, this is how to make one:

# "mkfs" means make filesystem, this creates a filesystem based
# on the entirety of your logical volume.
sudo mkfs.xfs /dev/vg-data/lv-data

# If "mkfs.xfs" doesn't work, just use "mkfs" which will use ext4 instead of xfs

Now to mount the file-system to your system:

# You can replace the "/data" folder with another name if you wish
sudo mkdir /data
sudo mount /dev/vg-data/lv-data /data

Option 2. Adding a new LV to existing file-system

If you already have a file-system that uses LVs and want to add another LV to it, you don’t need to make a new file-system for it, instead do:

resize2fs /dev/vg-data/lv-data

This will try and resize the file-system to the new size of your logical volume, assuming you added to it.

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