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How to resize root file system on RHEL 6

Here is the list of steps to reduce the  root file system (lv_root) on a RHEL 6 Linux server:

  • Boot the system into rescue mode. Do not mount the file systems (select the option to 'Skip' in the rescue mode and start a shell)
  • Bring the Volume Group online
    • #lvm vgchange -a -y
  • Run fsck on the FS
    • #e2fsck -f /dev/vg_myhost/lv_root
  • Resize the file system with new size
    • #resize2fs -f /dev/vg_myhost/lv_root 20G
  • Reduce the Logical Volume of the FS with the new size
    • #lvreduce -L20G /dev/vg_myhost/lv_root
  • Run fsck to make sure the FS is still ok
    • #e2fsck -f /dev/vg_myhost/lv_root
  • Optionally mount the file system in the rescue mode
    • #mkdir -p /mnt/sysimage/root
    • #mount -t ext4 /dev/mapper/vg_myhost-lv_root /mnt/sysimage/root
    • #cd /mnt/sysimage/root
  • Unmount the FS
    • #cd
    • #umount /mnt/sysimage/root
  • Exit rescue mode and boot the system from the hard disk
    • #exit
  • Select the reboot option from the recue mode

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