Hi I need to increase root partition space by reducing /home, in a Centos 6.6,my situation is this:

/dev/mapper/VolGroup-lv_root      50G   46G  1,6G  97% / 
tmpfs                            1,9G     0  1,9G   0% /dev/shm 
/dev/sda1                        477M   61M  391M  14% /boot 
/dev/mapper/VolGroup-lv_home     140G  3,9G  129G   3% /home

Is it possible?


It is not something I would do online but I think it is possible. I guess you are using ext4.

  1. umount /home

    $ umount /home
  2. shrink the /home filesystem

    $ fsck -f /dev/mapper/VolGroup-lv_home
    $ resize2fs /dev/mapper/VolGroup-lv_home 80G
  3. shrink the /home logical volume

    $ lvreduce -L -40G /dev/mapper/VolGroup-lv_home
  4. resize the /home partition to the size of the LV

    $ resize2fs /dev/mapper/VolGroup-lv_home
  5. extend the /root logical volume

    $ lvextend -L +40G /dev/mapper/VolGroup-lv_root
  6. extend the /root filesystem

    $ fsck -f /dev/mapper/VolGroup-lv_root
    $ resize2fs /dev/mapper/VolGroup-lv_root
  7. mount /home

    $ mount /home
  • is there any chances to lose data of home? – Rahul Sharma Jun 25 '18 at 11:14
  • 1
    Worked fine for me. Only thing I couldn’t do was the fsck call in (6) because the volume was mounted. – orange Nov 7 '18 at 10:23

Jodka is right. Here is the procedure.

umount /home
e2fsck -f /dev/mapper/vg_oracle-lv_home
resize2fs /dev/mapper/vg_oracle-lv_home 20G
lvreduce -L 20G /dev/mapper/vg_oracle-lv_home
lvextend -l +100%FREE /dev/mapper/vg_oracle-lv_root
resize2fs /dev/mapper/vg_oracle-lv_root
mount /home

Ref. Online resize LVM partitions


You cannot resize or change at all any partition on a storage device that is currently mounted. That means that your system needs to be shutdown if you intend to modify the root partition (since you cannot unmount it)

You will need to boot in an external OS (e.g. using a live-CD) to perform these tasks. I would recommend you to backup any sensible data before doing anything with the partitions.

  • I don't think that's true. Don't you think my answer would work? – Jodka Lemon Jul 1 '15 at 23:02
  • It is generally true, or at least it is generally true if you want to do it safely. Normally tools do not allow to modify mounted partitions. I have done a little bit more research and found this in askubuntu: askubuntu.com/questions/24027/… So I take that ext4 is an exception to what I said and you can do it on the fly (and therefore, your answer should work) – dave_alcarin Jul 2 '15 at 6:48

If you can use GUI, then with a help of system-config-lvm this can be made in an easy graphical way.

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