Table of Contents

Creating a logical volume and volume group

• Make sure the physical disk is listed as block device

• Create a new primary partition on the disk (partition type = 8e)

fdisk /dev/sdx # Replace "sdx" with your block device real name
n # create new partition 
p # New primary partition  
1 # select Partition number (1-4) <Enter>
# partition size: Accept the default values in case you want to use the full disk available space
t # set partition type LVM linux is 8e 
1 # select partition 
8e # for linux lvm 
w # to write 

• Create a new physical volume related to the partition created above

# Physical volume creation (Replace sdx with your block device name)
pvcreate /dev/sdx1

• Create a new volume group and include the pv mentioned above to it

vgcreate testdata_vg /dev/sdx1

• Create a new logical volume as child of the volume group above, you can specify a constant size or use 100% of the volumes currently part of the volume group above

Sample 1: New logical volume with size 20 GB
lvcreate -L 20000 -n vol01 testdata_vg 

Sample 2: New logical volume using 100% of available space
lvcreate -l 100%FREE -n vol01 testdata_vg

• Format the logical volume created above

Sample: Format as ext4
mkfs.ext4 /dev/testdata_vg/vol01

You can now mount the volume (device name: /dev/testdta_vg/vol01).

Extending an exiting logical volume

Adding an extra disk

• Make sure the new disk is listed as block device (lsblk)
• Create a new partition on the new disk and set the type to 8e (see instructions above)
• Create a new physical volume

pvcreate /dev/sdx1

• Extend the volume group adding the new pv to the volume group

vgextend /dev/testdata_vg /dev/sdx1

• Extend the logical volume so that is can use all space available now on the volume group

lvextend -l +100%FREE /dev/testdata_vg/vol01

• Double check that the new volume is now part of the existing volume group (lsblk)
• Unmount the volume group

umount /your_volume_group_mount_point

• Check the file system integrity (ext filesystems only)

e2fsck -f /dev/testdata_vg/vol01

• Extend the file system (command for ext file systems)

resize2fs /dev/testdata_vg/vol01

• Extend the file system (command for xfs file systems)

Make sure that volume group is mounted before to issue the command below

xfs_grows /dev/testdata_vg/vol01

• Mount the drive (if not already mounted . . .)

mount /your_volume_group_mount_point

• Double check that now the volume group is using all new available disk space

df -h

Adding extra space added to an already existing disk

• Check the current partitions on extended physical disk

fdisk -l /dev/sdx

• Create a new primary partition and set type to 8e (see instructions above)
• Create a new physical volume
• Extend the volume group adding the new physical volume to the volume group

vgextend /dev/testdata_vg /dev/sdx1

• Extend the logical volume so that is can use all available size of the volume group

lvextend -l +100%FREE /dev/testdata_vg/vol01

• Check the integrity (ext file systems only)

e2fsck -f /dev/testdata_vg/vol01

• Extend the file system (command for ext file systems)

resize2fs /dev/testdata_vg/vol01

• Extend the file system (command for xfs file systems)

Make sure that volume group is mounted before to issue the command below

xfs_grows /dev/testdata_vg/vol01

• Mount the drive (if not already mounted . . .)

mount /your_volume_group_mount_point

• Double check that now the volume group is using all new available disk space

df -h

Troubleshooting

mkfs command takes a very long time

To run mkfs without trim, use the -K option on XFS and -E nodiscard on ext4.

XFS:

mkfs.xfs -K /dev/sdx

EXT4:

mkfs.ext4 -E nodiscard /dev/sdx

lsblk/df does not show volume changes

Reload the partition table with the command ‘partprobe’

A new disk has been attached to the VM, but it’s not listed as block device

Option #1: Reboot the VM

Option #2: Force the OS to scan list of attached block devices:

for host in /sys/class/scsi_host/*; do echo "- - -" | sudo tee $host/scan; ls /dev/sd* ; done