1.查看磁盘文件信息，进行扩展

[root@vp-01 export]# qemu-img info test.qcow2
image: test.qcow2
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 2.1G
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false
    refcount bits: 16
    corrupt: false

2.增加磁盘容量大小20G

[root@vp-01 export]# qemu-img resize test.qcow2 +20G
Image resized.

[root@vp-01 export]# qemu-img info test.qcow2
image: test.qcow2
file format: qcow2
virtual size: 40G (42949672960 bytes)
disk size: 2.1G
cluster_size: 65536
Format specific information:
    compat: 1.1
    lazy refcounts: false
    refcount bits: 16
    corrupt: false