Linux CENTOS7 LVM

Question

Here's the output of my df -kh

Filesystem               Size  Used Avail Use% Mounted on
/dev/mapper/centos-root   50G   34G   17G  67% /
devtmpfs                 2.5G     0  2.5G   0% /dev
tmpfs                    2.5G  140K  2.5G   1% /dev/shm
tmpfs                    2.5G  8.9M  2.5G   1% /run
tmpfs                    2.5G     0  2.5G   0% /sys/fs/cgroup
/dev/sda1                497M  133M  365M  27% /boot

I'd like to increase the size of / by 194 GB.

I ran the command lvextend -L +194G /dev/mapper/centos-root I got he message that the filesystem has been resized. I rebooted the system. I'm expecting to see my / to be 244GB. However it isn't

VOLUME GROUP DETAILS

[root@localhost mapper]# vgdisplay
  --- Volume group ---
  VG Name               centos
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  6
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               249.51 GiB
  PE Size               4.00 MiB
  Total PE              63874
  Alloc PE / Size       63648 / 248.62 GiB
  Free  PE / Size       226 / 904.00 MiB
  VG UUID               icZPDf-z0cO-5qMl-Gbtr-XisU-6ptl-cpG3dz

LOGICAL VOLUME DETAILS

[root@localhost mapper]# lvdisplay
  --- Logical volume ---
  LV Path                /dev/centos/swap
  LV Name                swap
  VG Name                centos
  LV UUID                MzofJC-7I6W-XcM9-xwrT-Ns86-LdYt-OYltON
  LV Write Access        read/write
  LV Creation host, time localhost, 2015-07-02 09:04:52 +1200
  LV Status              available
  # open                 2
  LV Size                4.62 GiB
  Current LE             1184
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:1

  --- Logical volume ---
  LV Path                /dev/centos/root
  LV Name                root
  VG Name                centos
  LV UUID                1J50kj-hcBC-T5rY-y6LV-0xEI-ZVId-qBfgQl
  LV Write Access        read/write
  LV Creation host, time localhost, 2015-07-02 09:04:53 +1200
  LV Status              available
  # open                 1
  LV Size                244.00 GiB
  Current LE             62464
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0



 /etc/fstab OUTPUT

#
# /etc/fstab
# Created by anaconda on Thu Jul  2 09:04:53 2015
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos-root /                       xfs     defaults        0 0
UUID=c4f605aa-56b0-4bde-ae0b-ddf6f0e4a983 /boot                   xfs     defaults        0 0
#/dev/mapper/centos-home /home                   xfs     defaults        0 0
/dev/mapper/centos-swap swap                    swap    defaults        0 0

How do I extend /dev/mapper/centos-root? Any help?

This question is not programming related. It is off topic for this site. — nobody, Jul 17 '15 at 01:45

score 0 · Answer 1 · answered Jul 19 '15 at 09:02

Instead of "lvextend -L +194G /dev/mapper/centos-root", use "lvextend -L +194G -r /dev/mapper/centos-root". The -r option changes the logical volume and the associated file system sizes in only one step. In addition, this works for ext4 and xfs. Also, don't use "df", use "lsblk", the display is much clearer.

User12345 · Accepted Answer · 2015-07-17T01:20:49.390

AH, I hadn't bumped on this link - https://themacwrangler.wordpress.com/2015/01/16/re-sizing-partitions-in-centos7/. Very helpful.

I had to grow the filesystem too which I hadn't. Good learning.

Copying the contents of the page at the above link here just in case the content becomes unavailable in future.

Re-sizing partitions in Centos7

By default in a CentOS7 install we get a couple of partitions created for the root user and one for home usually something like this:

# df -h
Filesystem                                   Size  Used Avail Use% Mounted on
/dev/mapper/centos-root                       50G  2.7G   48G   6% /
devtmpfs                                     239M     0  239M   0% /dev
tmpfs                                        246M     0  246M   0% /dev/shm
tmpfs                                        246M   29M  217M  12% /run
tmpfs                                        246M     0  246M   0% /sys/fs/cgroup
/dev/mapper/centos-home                       29G   33M   29G   1% /home
/dev/sda1                                    497M   96M  401M  20% /boot


Note that the root partition is 50Gb and the home partition is 29Gb

Often I find myself wanting or needing to remove the centos-home partition and expand the centos-root partition.

It is a pretty straight forward exercise, but one that I often forget the steps involved.

So here they are:
• First backup any data that might exist in /home so you can restore it later.
• Unmount the centos-home partition.

# umount /home/

• Next show the logical volumes.

# lvdisplay
  --- Logical volume ---
  LV Path                /dev/centos/swap
  LV Name                swap
  VG Name                centos
  LV UUID                azXfXa-YPiG-Bx9x-NfIO-eswN-iHVw-YsXpYe
  LV Write Access        read/write
  LV Creation host, time localhost, 2014-12-01 13:02:00 +1100
  LV Status              available
  # open                 2
  LV Size                1.03 GiB
  Current LE             264
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:1

  --- Logical volume ---
  LV Path                /dev/centos/home
  LV Name                home
  VG Name                centos
  LV UUID                LtYf7h-h1kx-p7OR-ZdN8-2Xo8-KXYT-uC2Roa
  LV Write Access        read/write
  LV Creation host, time localhost, 2014-12-01 13:02:01 +1100
  LV Status              available
  # open                 0
  LV Size                28.48 GiB
  Current LE             7290
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:2

  --- Logical volume ---
  LV Path                /dev/centos/root
  LV Name                root
  VG Name                centos
  LV UUID                DjnSO6-gsbN-g83Q-VhfC-u3Ft-8DqY-sPMx35
  LV Write Access        read/write
  LV Creation host, time localhost, 2014-12-01 13:02:03 +1100
  LV Status              available
  # open                 1
  LV Size                50.00 GiB
  Current LE             12800
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0

•Now remove the logical volume for centos-home.

# lvremove /dev/centos/home
Do you really want to remove active logical volume home? [y/n]: y
Logical volume "home" successfully removed

•You should now have the free space available in VFree when you have a look using vgs.

# vgs
  VG                #PV #LV #SN Attr   VSize  VFree 
  centos              1   2   0 wz--n- 79.51g 28.48g

• Now resize the centos-root partition.

# lvresize -L +28.47GB /dev/mapper/centos-root 
  Rounding size to boundary between physical extents: 28.47 GiB
  Extending logical volume root to 78.47 GiB
  Logical volume root successfully resized


Note that I expanded the partition by slightly less than the available space, 28.47Gb instead of 28.48Gb, this is just to make sure you avoid hitting an insufficient free space error.
• Grow the partition to use all the free space

#xfs_growfs /dev/mapper/centos-root

• Confirm your new partition size.

# df -h
Filesystem                             Size  Used Avail Use% Mounted on
/dev/mapper/centos-root                 79G  2.7G   76G   4% /
devtmpfs                               239M     0  239M   0% /dev
tmpfs                                  246M     0  246M   0% /dev/shm
tmpfs                                  246M   29M  217M  12% /run
tmpfs                                  246M     0  246M   0% /sys/fs/cgroup
/dev/sda1                              497M   96M  401M  20% /boot

Linux CENTOS7 LVM

2 Answers2