Virt-resize

virt-resize - Resize a virtual machine disk https://linux.die.net/man/1/virt-resize

Example

Reference: http://wiki.docking.org/index.php/To_resize_a_virtual_drive

Overview: qemu-img resize -> virt-resize -> (Check virt-filesystems) -> lvextend --resizefs

0) Backup 

cp my_machine.qcow2 my_machine-ORIGIN.qcow2 (progress -m to track status)

1) qemu-img resize image_name.qcow2 +3G

2) Resize:

virt-resize --expand /dev/sda4 my_machine-ORIGIN.qcow2 my_machine-DESTINATION.qcow2

3) Verify name of your devices you can use:

virt-filesystems --partitions --long -a VM_NAME.qcow2

4) lvextend --resizefs or fdisk

5) Start your machine: virsh start VM_NAME and discard your backups if everything is working properly.

• Virt resize execution examples

Virt-resize execution with errors

Failed to get "write" lock

virt-resize: error: libguestfs error: guestfs_launch failed.
This usually means the libguestfs appliance failed to start or crashed.
Do:
  export LIBGUESTFS_DEBUG=1 LIBGUESTFS_TRACE=1
and run the command again.  For further information, read:
  http://libguestfs.org/guestfs-faq.1.html#debugging-libguestfs
You can also run 'libguestfs-test-tool' and post the *complete* output
into a bug report or message to the libguestfs mailing list.

If reporting bugs, run virt-resize with debugging enabled and include the
complete output:

  virt-resize -v -x [...]


After debugging: 
 qemu-system-x86_64: -drive file=/path/to/image/VM_NAME.qcow2,cache=unsafe,id=hd1,if=none: 
 Failed to get "write" lock
 Is another process using the image?

partition not found in the source disk image

libguestfs: trace: lvs = []
libguestfs: trace: canonical_device_name "/dev/vdb1"
libguestfs: trace: canonical_device_name = "/dev/sdb1"
virt-resize: error: /dev/sdb1: partition not found in the source disk image
(this error came from '--expand' option on the command line).  Try running
this command: virt-filesystems --partitions --long -a
VM_NAME.qcow2

No such file or directory

virt-resize --expand /dev/sda1 IMAGE.qcow2 IMAGE-DST.qcow2
[   0.0] Examining IMAGE.qcow2
virt-resize: error: libguestfs error: IMAGE-DST.qcow2: No such file or directory

If reporting bugs, run virt-resize with debugging enabled and include the
complete output:

 virt-resize -v -x [...]

Related commands

• qemu-img resize
• lvextend --resizefs
• virt-filesystems
• virt-df
• virsh blockresize
• --LV-expand option from virt-resize

Activities

• Extend LVM on qcow2 images

See also

• KVM, Installation, QEMU, virsh, virtinst, libguestfs-tools, libvirt, qemu, Red Hat Virtualization (RHV), MacVTap, Virtio, oVirt, KVM services, KVM networking, KVM graphics, CPU, KVM on ARM
• libguestfs-tools: virt-sysprep, virt-clone, virt-builder, virt-customize, virt-resize, virt-rescue, virt-sparsify, guestmount, guestfish, virt-inspector, virt-cat, virt-log, virt-df, virt-ls, virt-filesystems, virt-list-filesystems, virt-edit