Redhat - Reduce size of root file system

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