CentOS / RHEL Disk space re-sizing / Reallocation

Disk space rallocation in Linux-RHEL/CentoOS

Reducing the size of the /home/ from 500GB to 50GB and allocating it /root

scenario :

[root@cloud ~]# df -h /home/
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_cloud-LogVol00
                             12G  9.2G  1.9G  84% /home

Follow the steps :

Step 1:

unmount the the /home

[root@openstack ~]# umount /home/



Step 2:

check the filesystem for Errors using e2fsck command.





[root@openstack ~]# e2fsck -f /dev/mapper/vg_openstack-lv_home

e2fsck 1.41.12 (17-May-2010)

Pass 1: Checking inodes, blocks, and sizes

Pass 2: Checking directory structure

Pass 3: Checking directory connectivity

Pass 4: Checking reference counts

Pass 5: Checking group summary information

/dev/mapper/vg_openstack-lv_home: 11/3276800 files (0.0% non-contiguous), 251699/13107200 blocks

[root@openstack ~]#





Note: In the above command e2fsck , we use the option '-f' to forcefully check the filesystem , even if the filesystem is clean.




Step 3:

Shrink the size of /home to desire size.






[root@openstack ~]# resize2fs /dev/mapper/vg_openstack-lv_home 50G resize2fs 1.41.12 (17-May-2010) Resizing the filesystem on /dev/mapper/vg_openstack-lv_home to 13107200 (4k) blocks. The filesystem on /dev/mapper/vg_openstack-lv_home is now 13107200 blocks long.







Step 4:

Now reduce the size using lvreduce command.




[root@openstack ~]# lvreduce -L 50G /dev/mapper/vg_openstack-lv_home

  WARNING: Reducing active logical volume to 50.00 GiB

  THIS MAY DESTROY YOUR DATA (filesystem etc.)

Do you really want to reduce lv_home? [y/n]: y

  Reducing logical volume lv_home to 50.00 GiB

  Logical volume lv_home successfully resized





Step 5:

For the safer side , now check the reduced filesystem for errors

[root@openstack ~]# e2fsck -f /dev/mapper/vg_openstack-lv_home e2fsck 1.41.12 (17-May-2010) Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information /dev/mapper/vg_openstack-lv_home: 11/3276800 files (0.0% non-contiguous), 251699/13107200 blocks [root@openstack ~]#

Step 6:  

 Mount the file system and verify the size.

[root@openstack ~]# mount /home/
[root@openstack ~]# df -kh
Filesystem                        Size  Used Avail Use% Mounted on
/dev/mapper/vg_openstack-lv_root   50G  6.0G   41G  13% /
tmpfs                              16G  228K   16G   1% /dev/shm
/dev/sda1                         485M   40M  420M   9% /boot
/dev/mapper/vg_openstack-lv_home   50G  180M   47G   1% /home

Step 7:

Resize the desired partition with required space

lvextend -L 75G /dev/mapper/vg_openstack-lv_root

resize2fs /dev/mapper/vg_openstack-lv_root

check the sze of the partion changes 

df -kh

and you done resizing the partition.