Welcome to our guide on how to extend root filesystem using LVM on Linux. This will cover both ext4 and XFS filesystem root partition extending. To demonstrate a complete LVM lifecycle, we will perform the following actions:
- Create an LVM physical volume, volume group, and logical volume.
- Create an XFS and ext4 file systems on the logical volumes
- Extend LVM logical volumes ( root and non-root filesystem)
LVM allows you to create, resize or delete partitions on a running system without requiring any reboot. So check the steps below to extend root filesystem using LVM in Linux. You can skip some steps which don’t apply to use.
Run all the commands below as root or with sudo.
Step 1: Confirm Disk Partitions in Distribution.
Before we can do any extension, let’s just confirm our origional disk layout / partitioning scheme.
# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 1024M 0 rom
vda 252:0 0 30G 0 disk
├─vda1 252:1 0 1M 0 part
├─vda2 252:2 0 1G 0 part /boot
└─vda3 252:3 0 29G 0 part
└─ubuntu--vg-ubuntu--lv 253:0 0 29G 0 lvm /As noted, we have a root filesystem on /dev/vda3 physical volume.
# pvs
PV VG Fmt Attr PSize PFree
/dev/vda3 ubuntu-vg lvm2 a-- <29.00g 0 Step 2: Extend your OS root disk
As shown in step 1, my root filesystem is on a 30GB disk. I’ll grow it to 40GB by extending the virtual disk (VM disk device).
I use KVM virtualization technology, so this guide works for me: How to extend/increase KVM Virtual Machine (VM) disk size
# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 1024M 0 rom
vda 252:0 0 40G 0 disk
├─vda1 252:1 0 1M 0 part
├─vda2 252:2 0 1G 0 part /boot
└─vda3 252:3 0 29G 0 part
└─ubuntu--vg-ubuntu--lv 253:0 0 29G 0 lvm /If you’re on a different Virtualization platform, refer to its documentation for how to extend OS disk.
Once the OS block device is resized, ssh to your Linux machine and extend LVM to use newly added disk capacity. The command below will expand the last partition (Partition 3), as shown by 252:3,on the disk (/dev/vda) to the maximum size the disk provides.
Install cloud utils package on the system
For those new to growpart, it is a Linux command line tool used to extend a partition in a partition table to fill available space. This command is provided by cloud utils package.
On Ubuntu / Debian system, run the commands below to install growpart tool.
# apt install cloud-guest-utilsFor CentOS server, run
yum -y install cloud-utils-growpartHelp page can be viewed by passing -h argument
# growpart -h
growpart disk partition
rewrite partition table so that partition takes up all the space it can
options:
-h | --help print Usage and exit
--fudge F if part could be resized, but change would be
less than 'F' bytes, do not resize (default: 1048576)
-N | --dry-run only report what would be done, show new 'sfdisk -d'
-v | --verbose increase verbosity / debug
-u | --update R update the the kernel partition table info after growing
this requires kernel support and 'partx --update'
R is one of:
- 'auto' : [default] update partition if possible
- 'force' : try despite sanity checks (fail on failure)
- 'off' : do not attempt
- 'on' : fail if sanity checks indicate no support
Example:
- growpart /dev/sda 1
Resize partition 1 on /dev/sdNow use growpart to extend your partition. In this example we’re extending partition 3 in disk /dev/vda. Replace 2and /dev/vda with your correct values.
# growpart /dev/vda 3
CHANGED: partition=3 start=2099200 old: size=18872320 end=20971520 new: size=60815327,end=62914527Confirm if the change was successful.
# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 1024M 0 rom
vda 252:0 0 40G 0 disk
├─vda1 252:1 0 1G 0 part /boot
└─vda2 252:2 0 39G 0 part
├─rhel-root 253:0 0 26.9G 0 lvm /
└─rhel-swap 253:1 0 2.1G 0 lvm [SWAP]Step 3: Resize root logical volume to occupy all space
Resize physical volume.
# pvresize /dev/vda3
Physical volume "/dev/vda3" changed
1 physical volume(s) resized or updated / 0 physical volume(s) not resized
# pvs
PV VG Fmt Attr PSize PFree
/dev/vda2 rhel lvm2 a-- <39.00g 10.00gCheck the size of the volume group configured.
# vgs
VG #PV #LV #SN Attr VSize VFree
rhel 1 2 0 wz--n- <39.00g 10.00gThen resize logical volume used by the root file system using the extended volume group:
lvextend -r -l +100%FREE /dev/name-of-volume-group/rootThis extends the logical volume to use all available capacity in the volume group. With the + sign the value is added to the actual size of the logical volume.
Command options used:
- -l – extend or set the logical volume size in units of logical extents
- -r – Resize underlying filesystem together with the logical volume
Here’s an example of my setup file system extension:
# df -hT | grep mapper
/dev/mapper/rhel-root xfs 27G 1.9G 26G 8% /
# lvextend -r -l +100%FREE /dev/ubuntu-vg/ubuntu-lv
Size of logical volume rhel/root changed from <26.93 GiB (6893 extents) to <36.93 GiB (9453 extents).
Logical volume rhel/root successfully resized.If you prefer setting the size to be extended manually, use command option:
-L, --size [+]LogicalVolumeSize[bBsSkKmMgGtTpPeE]Where size suffix are:
- M for megabytes
- G for gigabytes
- T for terabytes
- P for petabytes
- E for exabytes
Without the + sign the value is taken as an absolute one. Add 20 gigabytes to the current logical volume size
# lvextend -r -L +20G /dev/name-of-volume-group/rootStep 4: Check the new filesystem size
Your root filesystem will still show the old size.
# df -hT | grep mapper
/dev/mapper/ubuntu--vg-ubuntu--lv ext4 40G 26G 14G 65% /Let’s make the filesystem report the actual size, including extended.
For ext4 filesystem
resize2fs /dev/name-of-volume-group/rootFor xfs filesystem
# sudo xfs_growfs /
meta-data=/dev/mapper/rhel-root isize=512 agcount=4, agsize=1764608 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=1, rmapbt=0
= reflink=1
data = bsize=4096 blocks=7058432, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0, ftype=1
log =internal log bsize=4096 blocks=3446, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 7058432 to 9679872