135 lines
3.7 KiB
Markdown
135 lines
3.7 KiB
Markdown
---
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title: Resize an existing virtual disk
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description:
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published: true
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date: 2024-07-13T13:33:59.560Z
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tags:
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editor: markdown
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dateCreated: 2021-11-13T11:41:29.087Z
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---
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# Resize a disk
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## Background
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A virtual machine's disk may have to be resized, typically due to lack of space. This page explains how to do so.
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## Usage for Linux guests
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> In-place expansion is not supported. A new disk of the desired size has to be created.
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{.is-info}
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* Navigate to the location that contains the existing image
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```
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cd /var/lib/libvirt/images
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```
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* Create a new blank disk image of the desired size
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Use the following command to create a disk of 20 GB called `guest_20G.img`.
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```
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qemu-img create -f raw guest_20G.img 20G
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```
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* Identify the filesystem layout of the existing disk `guest.img`
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```
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# virt-filesystems -a -l -h guest.img
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Name Type VFS Label Size Parent
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/dev/vda1 filesystem vfat EFI 133935104 -
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/dev/vda2 filesystem ext4 boot 366869504 -
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/dev/vda3 filesystem ext4 root 9933475840 -
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```
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One can tell that the root partition is located under `/dev/vda3`. This is the one that will need to be expanded.
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* Copy the formet old data to the new disk and expand the root partition of the said disk
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> This command is cabable of expanding different kinds of filesystems, including `ext4` and `btrfs`
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{.is-info}
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```
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# virt-resize --expand /dev/vda3 guest.img guest_20G.img
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```
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* Review the changes
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```
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[ 0.0] Examining guest_20G.img
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**********
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Summary of changes:
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/dev/vda1: This partition will be left alone.
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/dev/vda2: This partition will be left alone.
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/dev/vda3: This partition will be resized from 10G to 20G. The
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filesystem ext4 on /dev/vda3 will be expanded using the ‘resize2fs’
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method.
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**********
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[ 2.1] Setting up initial partition table on guest_20G.img
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[ 12.9] Copying /dev/vda1
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[ 13.1] Copying /dev/vda2
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[ 13.4] Copying /dev/vda3
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100% ⟦▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒⟧ 00:00
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[ 38.3] Expanding /dev/vda3 using the ‘resize2fs’ method
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Resize operation completed with no errors. Before deleting the old disk,
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carefully check that the resized disk boots and works correctly.
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```
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* Switch to the new disk for your virtual machine
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Now that the new disk has been created, it can be used in the virtual machine.
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```
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# virsh edit guest
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```
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Locate the source line for the existing disk `guest.img`:
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```
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[...]
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<disk type='file' device='disk'>
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<driver name='qemu' type='raw' cache='writeback' discard='unmap'/>
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<source file='/var/lib/libvirt/images/guest.img'/>
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<target dev='vda' bus='virtio'/>
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<address type='pci' domain='0x0000' bus='0x04' slot='0x00' function='0x0'/>
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</disk>
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[...]
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```
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Edit the said line so that it points to the new disk `guest-20G.img`:
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```
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[...]
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<disk type='file' device='disk'>
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<driver name='qemu' type='raw' cache='writeback' discard='unmap'/>
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<source file='/var/lib/libvirt/images/guest-20G.img'/>
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<target dev='vda' bus='virtio'/>
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<address type='pci' domain='0x0000' bus='0x04' slot='0x00' function='0x0'/>
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</disk>
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[...]
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```
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Start the virtual machine and ensure that it is working properly. If it does, the former disk could be removed.
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## Resources
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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.*"
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* Installation
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On Fedora-related distributions, `virt-resize` is provided by the `guestfs-tools` package :
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```
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# dnf install guestfs-tools
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```
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---
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*[**Go to parent page**](https://wiki.phyllo.me/)* |