How to online resize LVM2 partitions size

Jephe Wu  -

Environment: Fedora 3 or RHEL servers with LVM partitions
Objective: online increase partitions size including /, /usr, /var partitions


1.  login as root, run 'vgdisplay' to find out the free PE extend and size

  Total PE              2039
  Alloc PE / Size       1745 / 54.53 GB
  Free  PE / Size       294 / 9.19 GB

2. run 'vgdisplay -v' to find out the logical volume LV name which you want to increase, let's say it's /dev/VolGroup00/LogVol06

3. increase the 5 Physical Extent(PE)
lvm lvresize -l +5 /dev/VolGroup00/LogVol06

4. use resize2fs(RHEL 4, 5) or ext2online(Fedora, starting from Fedora 6, this command is removed) to online increase partition file system size

ext2online /dev/VolGroup00/LogVol06 [newsize]
resize2fs  /dev/VolGroup00/LogVol06

Online reduce a /data/ partition and increase / partition
Objective: LVM partitions allocation is done, there's no free PE available already, need to reduce /data partition and increase / partition
Environment: CentOS 5.4, reduce /data from 100g to 50g, and increase / from 15g to 30g, still left 35g free for future
umount /data
e2fsck -f /dev/VolGroup01/LogVol02
resize2fs /dev/VolGroup01/LogVol02 50G
lvreduce -L 50G /dev/VolGroup01/LogVol02
e2fsck -f /dev/VolGroup01/LogVol02

# online increase / partition from 15G to 30G and increase file system to make use of the full 30G space
lvresize -L 30G /dev/VolGroup01/LogVol00
resize2fs /dev/VolGroup01/LogVol00

vgdisplay -v

Use RIP Linux to shrink LVM root partition for default CentOS 5.3

Environment: default installation of CentOS 5.3 with a very bit /root LVM partition
Objective: reduce the root LVM partition to 20G file system size


1. boot up with a RIP Linux CD
2. run command 'lvm -a y VolGroup00' to activate the volume group and logical volumes
3. resize2fs /dev/VolGroup00/LogVol00 20G
4. lvm lvresize --size 20G /dev/VolGroup00/LogVol00
note: to be very safe, you might want to resize logical volume to 21G instead of 20G, but according to the article from redhat access below, it's not required.
5. reboot

How do I reduce the size of the root file system after installation Red Hat Enterprise Linux 5?

I have attached above article from redhat below:

Release Found: Red Hat Enterprise Linux 5

The default file system layout from the Red Hat Enterprise Linux 5 installation process includes a special space for /boot and swap space then gives all left space to one logical volume and used the logical volume as root / volume.

Integrating all data files and system files in one file system is not always an ideal choice for production systems. If the system cannot be reinstalled, it is possible to reduce the size of the root file system and the logical volume on which it resides.

Reducing the logical volume on the root / volume must be done in rescue mode.

First, boot the system from Red Hat Enterprise Linux 5 Disc 1, and at the prompt, type linux rescue and press enter. When prompted for language, and keyboard, provide the pertinent information for the system. When prompted to enable the network devices on the system, select "No." Finally, select "Skip" when prompted to allow the rescue environment to mount Red Hat Enterprise Linux installation under the /mnt/sysimage directory. The filesystems MUST NOT be mounted to carry out the following steps.

Next run following commands to scan all disks LVM2 volume groups:

# lvm.static vgscan

Next, activate the logical volume to reduce. In this example, /dev/VolGroup00/LogVol00 was made available with the following command:

# lvm.static lvchange -ay /dev/VolGroup00/LogVol00

Next, reduce the size of file system and logical volume on /dev/VolGroup00/LogVol00. Please make sure there is enough space left on the root / file system and that the logical volume is large enough to contain all the data that was previously present. If the file system is at close to being full, for example, this may not work. Before resizing file system, run e2fsck to check file system first.

# e2fsck -f /dev/VolGroup00/LogVol00
# resize2fs /dev/VolGroup00/LogVol00 3000M
# lvm.static lvreduce -L 3000M /dev/VolGroup00/LogVol00

Please note that this is done on /dev/VolGroup00/LogVol00. The number at the end is the final size of the file system, not the amount it is reduced by.

Finally, verify the modification then reboot the system.

# lvm.static vgdisplay VolGroup00
# exit

WARNING: Resizing an active logical volume can cause catastrophic data loss if carried out incorrectly. Plan and act accordingly. ALWAYS create backups!


 How to remove a LVM partition forcely?

# kpartx -d xxxx