wiki/resize.md

title	description	published	date	tags	editor	dateCreated
Resize a guest disk image	Resize a a guest disk image using qemu-img and virt-resize	true	2021-11-01T23:40:55.146Z		markdown	2021-08-12T10:55:58.877Z

qemu-img and virt-resize

Introduction

As per the software description : "qemu-img allows you to create, convert and modify images offline. It can handle all image formats supported by QEMU."

Expanding a new disk implies creating a new blank image of the desired size and "copy" the existing disk into this new bigger image using virt-resize.

In-place expansion is not supported, which mean than a copy of the disk to be expanded has to be created {.is-info}

Installation

• On Fedora-related distributions, virt-resize is provided by the guestfs-tools package :

# dnf install guestfs-tools

Usage

• Create a new disk image

In-place expansion is not supported. A new disk of the desired size has to be created.

Use the following command to create phyllome_but_bigger.img, a disk of 15 GiB

$ qemu-img create -f raw phyllome-bigger.img 15G

• Expand the root partition

This command only works if the root partition is located on vda3 and if the disk image filesystem uses EXT4.
{.is-warning}

This command bellow requires root privileges.

# virt-resize --expand /dev/vda3 phyllome.img phyllome_but_bigger.img

[   0.0] Examining phyllome.img
**********

Summary of changes:

/dev/vda1: This partition will be left alone.

/dev/vda2: This partition will be left alone.

/dev/vda3: This partition will be resized from 5G to 15G.  The 
filesystem ext4 on /dev/vda3 will be expanded using the ‘resize2fs’ 
method.

**********
[   2.1] Setting up initial partition table on phyllome-bigger.img
[  12.9] Copying /dev/vda1
[  13.1] Copying /dev/vda2
[  13.4] Copying /dev/vda3
 100% ⟦▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒⟧ 00:00
[  38.3] Expanding /dev/vda3 using the ‘resize2fs’ method

Resize operation completed with no errors.  Before deleting the old disk, 
carefully check that the resized disk boots and works correctly.

• Inform your virtual machine to use the new disk

To-do