KVM : Expand an existing partition(xfs) size
Here is how to expand an existing partition size of qcow2 images.1. List partitions of a qcow2 image you would like to expand
[hattori@centos ~]$ sudo yum install -y libguestfs-xfs.x86_64
[root@centos ~]# cd /var/lib/libvirt/images/
[root@centos images]# virsh dumpxml lab05-u | grep qcow2
<driver name='qemu' type='qcow2'/>
<source file='/var/lib/libvirt/images/lab05-u.qcow2'/>
[root@centos images]#
[root@centos images]# virt-filesystems --long -h --all -a ./lab05-u.qcow2
Name Type VFS Label MBR Size Parent
/dev/sda1 filesystem xfs - - 1.0G -
/dev/sda2 filesystem swap - - 4.0G -
/dev/sda3 filesystem xfs - - 35G -
/dev/sda1 partition - - 83 1.0G /dev/sda
/dev/sda2 partition - - 82 4.0G /dev/sda
/dev/sda3 partition - - 83 35G /dev/sda
/dev/sda device - - - 40G -
[root@centos images]#
2. Extend the size of a file
[root@centos images]# truncate -r ./lab05-u.qcow2 new-lab05-u.qcow2
[root@centos images]# truncate -s +40G new-lab05-u.qcow2
[root@centos images]#
3. Expand a partition (/dev/sda3)
[root@centos images]# virt-resize --expand /dev/sda3 ./lab05-u.qcow2 ./new-lab05-u.qcow2
[ 0.0] Examining ./lab05-u.qcow2
**********
Summary of changes:
/dev/sda1: This partition will be left alone.
/dev/sda2: This partition will be left alone.
/dev/sda3: This partition will be resized from 35.0G to 75.0G. The
filesystem xfs on /dev/sda3 will be expanded using the ‘xfs_growfs’
method.
**********
[ 3.5] Setting up initial partition table on ./new-lab05-u.qcow2
[ 3.9] Copying /dev/sda1
100% ⟦▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒⟧ 00:00
[ 8.3] Copying /dev/sda2
100% ⟦▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒⟧ 00:00
[ 15.6] Copying /dev/sda3
100% ⟦▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒⟧ 00:00
[ 99.0] Expanding /dev/sda3 using the ‘xfs_growfs’ method
Resize operation completed with no errors. Before deleting the old disk,
carefully check that the resized disk boots and works correctly.
[root@centos images]#
[root@centos images]# qemu-img info new-lab05-u.qcow2
image: new-lab05-u.qcow2
file format: raw
virtual size: 80G (85906161664 bytes)
disk size: 3.6G
[root@centos images]#
4. Boot a VM with a new qcow2 image
Convert the image format to qcow2 and then launch the VM.[root@centos images]# qemu-img convert -f raw -O qcow2 ./new-lab05-u.qcow2 ./new-lab05-u.qcow2-new
[root@centos images]# qemu-img convert -f raw -O qcow2 ./new-lab05-u.qcow2 ./new-lab05-u.qcow2-new
[root@centos images]# qemu-img info ./new-lab05-u.qcow2-new
image: ./new-lab05-u.qcow2-new
file format: qcow2
virtual size: 80G (85906161664 bytes)
disk size: 3.8G
cluster_size: 65536
Format specific information:
compat: 1.1
lazy refcounts: false
[root@centos images]#
[root@centos images]# mv new-lab05-u.qcow2-new new-lab05-u.qcow2
mv: overwrite ‘new-lab05-u.qcow2’? y
[root@centos images]#
[root@centos images]# virsh start lab05-u
Domain lab05-u started
[user01@lab05-u ~]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/vda3 75G 3.4G 72G 5% /
devtmpfs 5.8G 0 5.8G 0% /dev
tmpfs 5.8G 4.0K 5.8G 1% /dev/shm
tmpfs 5.8G 776K 5.8G 1% /run
tmpfs 5.8G 0 5.8G 0% /sys/fs/cgroup
/dev/vda1 1014M 175M 840M 18% /boot
tmpfs 1.2G 0 1.2G 0% /run/user/1000
[user01@lab05-u ~]$
virt-resize