Extend a Disk

Extend a Disk #

In this guide, we’ll expand existing disks, using GParted, as well as fdisk, including partition expansions.

Extending an LVM partition with GParted #

Follow guide at own risk, resizing disks comes with risk, make sure you have backups. This guide assumes paths, make sure you’re running commands agains the correct drives/paths.

  1. Grow disk in Hypervisor
  2. Use Gparted to increase logical volume size
  3. Run vgdisplay - find the “VG Name”, in my sitation it’s d0
  4. Extend the LVM volume
lvextend -l +100%FREE /dev/d0/root
  1. expand the file system, either using resize2fs or xfx_growfs if using centOS and XFS This
xfs_growfs /dev/d0/root

Or this depending on FS type

resize2fs /dev/d0/root
  1. verify change has gone through
df -h

Extending an LVM partition with fdisk and without a reboot. #

You can do this without rebooting in CentOS 7. Assuming your disk is /dev/vda and standard RHEL/CentOS partitioning:
Extend partition

fdisk /dev/vda

Enter p to print your initial partition table.

Enter d (delete) followed by 2 to delete the existing partition definition (partition 1 is usually /boot and partition 2 is usually the root partition).

Enter n (new) followed by p (primary) followed by 2 to re-create partition number 2 and enter to accept the start block and enter again to accept the end block which is defaulted to the end of the disk.

Enter t (type) then 2 then 8e to change the new partition type to “Linux LVM”.

Enter p to print your new partition table and make sure the start block matches what was in the initial partition table printed above.

Enter w to write the partition table to disk. You will see an error about Device or resource busy which you can ignore.

Update kernel in-memory partition table

After changing your partition table, run the following command to update the kernel in-memory partition table:

partx -u /dev/vda

Resize physical volume
Resize the PV to recognize the extra space

pvresize /dev/vda2

Resize LV and filesystem

In this command centos is the PV, root is the LV and /dev/vda2 is the partition that was extended. Use pvs and lvs commands to see your physical and logical volume names if you don’t know them. The -r option in this command resizes the filesystem appropriately so you don’t have to call resize2fs or xfs_growfs separately.

lvextend -r centos/root /dev/vda2