Grow Disk Space on a CentOS 7 VM Using QEMU, LVM, and XFS

Be sure to backup any critical data.
Shutdown the virtual machine.
Increase the size of the disk image with the QEMU disk image utility.
qemu-img resize example.qcow2 +40G Image resized.
This increases the size of the disk image example.qcow2 by forty Gibibytes.
Start the virtual machine.
On the virtual machine, install the cloud-utils-growpart package from Canonical’s cloud-utils project.
```
sudo dnf -y install cloud-utils-growpart
```

List your disks and partitions with the lsblk command and note the device and partition you wish to expand.

lsblk
NAME                           MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
fd0                              2:0    1     4K  0 disk
sr0                             11:0    1  1024M  0 rom
vda                            252:0    0    80G  0 disk
├─vda1                         252:1    0     1G  0 part /boot
└─vda2                         252:2    0    59G  0 part
  ├─centos-root                253:0    0    37G  0 lvm  /
  ├─centos-swap                253:1    0   3.9G  0 lvm  [SWAP]
  └─centos-home                253:2    0  18.1G  0 lvm  /home

The home partition is low on space, so partition 2 on the device vda will be expanded because it contains centos-home.

Grow partition 2 on device vda with all the new free space on the disk image by using the growpart command.

sudo growpart /dev/vda 2
CHANGED: partition=2 start=2099200 old: size=123729920 end=125829120 new: size=207615967 end=209715167

Reboot the VM.

Expand the corresponding physical from new space available on the partition with pvresize.

sudo pvresize /dev/vda2
  Physical volume "/dev/vda2" changed
  1 physical volume(s) resized or updated / 0 physical volume(s) not resized

Use the df command, determine which logical volume is to be grown.

df -Th
Filesystem                             Type      Size  Used Avail Use% Mounted on
devtmpfs                               devtmpfs  1.9G     0  1.9G   0% /dev
tmpfs                                  tmpfs     1.9G     0  1.9G   0% /dev/shm
tmpfs                                  tmpfs     1.9G  9.2M  1.9G   1% /run
tmpfs                                  tmpfs     1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/mapper/centos-root                xfs        38G   15G   23G  40% /
/dev/vda1                              xfs      1014M  238M  777M  24% /boot
/dev/mapper/centos-home                xfs        19G   18G  213M  99% /home
tmpfs                                  tmpfs     379M   12K  379M   1% /run/user/42
tmpfs                                  tmpfs     379M     0  379M   0% /run/user/1001

The /dev/mapper/centos-home filesystem is ninety-nine percent full, so this is the volume that needs to be enlarged.

With lvextend, extend the logical volume to with the space just added to the physical volume.

sudo lvextend -l +100%FREE /dev/mapper/centos-home
  Size of logical volume centos/home changed from <18.09 GiB (4630 extents) to <58.09 GiB (14870 extents).
  Logical volume centos/home successfully resized.

Determine the filesystem path for the logical volume /dev/mapper/centos-home from the output of the lvdisplay command.

sudo lvdisplay
  --- Logical volume ---
  LV Path                /dev/centos/swap
  LV Name                swap
  VG Name                centos
  LV UUID                rEAof0-CesW-iUqd-dq11-9k8P-p82Y-9bMvMQ
  LV Write Access        read/write
  LV Creation host, time localhost, 2020-09-15 08:09:39 -0500
  LV Status              available
  # open                 2
  LV Size                <3.88 GiB
  Current LE             992
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:1

  --- Logical volume ---
  LV Path                /dev/centos/home
  LV Name                home
  VG Name                centos
  LV UUID                IPqAHo-dvhr-ha1L-qbwf-DcAw-yAu1-K1VM6O
  LV Write Access        read/write
  LV Creation host, time localhost, 2020-09-15 08:09:39 -0500
  LV Status              available
  # open                 1
  LV Size                <18.09 GiB
  Current LE             4630
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:2

  --- Logical volume ---
  LV Path                /dev/centos/root
  LV Name                root
  VG Name                centos
  LV UUID                fPqtH3-fYV2-UX79-M2qG-731D-hv8c-t5M0TA
  LV Write Access        read/write
  LV Creation host, time localhost, 2020-09-15 08:09:40 -0500
  LV Status              available
  # open                 1
  LV Size                <37.04 GiB
  Current LE             9481
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

The path is indicated by the field LV Path. The path for the home directory is /dev/centos/home.

Increase the filesystem’s size by passing the path /dev/centos/home to the xfs_growfs command.

sudo xfs_growfs /dev/centos/home
meta-data=/dev/mapper/home isize=512    agcount=5, agsize=1185024 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=4741120, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal               bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 4741120 to 15226880

Verify that more disk space is indeed available.

df -Th /home
Filesystem                             Type  Size  Used Avail Use% Mounted on
/dev/mapper/centos-home                xfs    59G   18G   41G  31% /home

Tutorial

Conclusion