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Questions tagged [qcow2]

24 questions
8
votes
1 answer

KVM/QEMU/libvirt image path suggestion file system and mount options

As simple KVM server I've got to store raw and qcow2 images on special path like: /kvm-storage I want to know what's the best practices for file system and mount options to set this path for achieve better performance. File system is it better to…
Mohammad Hossein Fattahizadeh
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4
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2 answers

How to enable zstd for your qcow2 files

In QEMU 5.1 zstd compression of your qcow2 files was introduced. But it's not described in the manual for qemu-img. How do you enable it?
MrCalvin
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4
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1 answer

qemu-img convert burning CPU for nothing

I'm trying to reduce the usage of a qcow2 image. I did the following: qemu-img convert -p -f qcow2 -O qcow2 my_img.qcow2.backup my_img.qcow2 I outputs 200192 bytes and progress is stuck at 0.00%. CPU usage is pegged at 100% and I let it go for 2…
CrazyCasta
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2
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1 answer

What happens if I run a VM while copying the qcow2 file / can I backup by copying the VM file while running?

I'm trying to understand how the write happens with a VM. It looks like running one is not blocked while copying it for a backup. Will the copy contain any modified files like the boot log? Or will it just copy from a 'shadow copy' like on…
alchemy
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2
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1 answer

Can qemu-img uncompress qcow2 file?

We can use the -c option for qemu-img to compress the qcow2 file, e.g., here, but at the cost of uncompressing it while using. Suppose I am given a compressed qcow2 file, does qemu-img have any option or command to uncompress this qcow2 file?…
zzzhhh
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2
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1 answer

Set L2 cache for QEMU qcow2 disk in virsh XML

In the QEMU commandline you can set a L2 cache for a disk using l2-cache-size=10M This option is not supported in Virsh XML but it should be able to use the XML element but I cannot get it to work. My disk element in my…
MrCalvin
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1
vote
1 answer

How to merge common parts of qemu qcow2 disks

I have a qemu image B.qcow2 that is a snapshot of A.qcow2. I created a copy of B.qcow2 by using cp B.qcow2 C.qcow2 and then worked on both B.qcow2 and C.qcow2 independently. Thus, B.qcow2 and C.qcow2 are eventually different but they have a common…
sebastien dontneedtoknowthat
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1 answer

After cloning a VM with virt-clone, how do I rename the newly created qcow2 file?

I wanted to build another server based on an existing config, so I performed the following: [user@box ~]# virt-clone --original serverA-rhel8 --name serverB-rhel8 --auto-clone Allocating 'serverA-rhel8-1-clone.qcow2' | 200 GB 00:00:16 As you…
a coder
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1
vote
1 answer

How to increase the root partition size of a virtual machine used by GNOME Boxes (QEMU)?

I use GNOME Boxes on Fedora 32 to virtualize a Fedora Silverblue installation. I did not setup a sophisticated/smart partitioning for my virtual Fedora and have run out of disk space on my virtual root partition. My objective is to be able to…
justjulian
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1 answer

How to create partitions on qcow2 image without reserving disk size

I want to install archlinux in UEFI mode so, I created image from virt-manager with size of 20GB. Then after booting into VM, I created 2 partition with fdisk named /dev/vda1 and /dev/vda2 with 512MB and what remained (19.5~GB) I changed the type of…
user254419
1
vote
0 answers

`qemu-nbd` list phantom partitions

When I mount a qcow2, like qemu-nbd --connect=/dev/nbd0 /path/image.qcow2, fdisk /dev/nbd0 -l lists me partition non visible on /dev/. And when I mount /dev/nbd0 /path It only mount what should be the first partition. And partx -a /dev/nbd0 gives…
aaa
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0 answers

virsh attach-disk only work with name vd* instead of sd*

I have an qcow2 image and want to attach another disk to it. # create new qcow2 disk qemu-img create -f qcow2 vm-disk2 500G Then I attach it as sdb: virsh attach-disk myvm /var/lib/libvirt/images/vm-disk2 sdb --persistent --live --subdriver…
Tuyen Pham
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1
vote
1 answer

How to clone a single partition from a HD to a qcow2 disk image for use in qemu-kvm?

Edit (1&2): I cloned my working OS (powered off, HD mounted on USB drive, > dd if=/dev/sdc1 of=/data/system.img The original SSD is as follows: > sfdisk -d /dev/sdc # partition table of /dev/sdc unit: sectors /dev/sdc1 : start= 63, size=…
asoundmove
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0
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cannot import qcow2 image in virt-manager to other vm

I have installed debian to a qcow2 image to prepare it for usage in a paravirtualized vm and have tried to import it on another vm. Virt-manager doesn't give any errors, however from the OVMF bios it refuses to boot the image(after navigating there…
MaxBrandtner
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0 answers

Archive qemu image

How do I archive qemu images with the same efficiency as gcloud This command stub show efficiency. Around 80% on pre installed images of OSes notorious for their install size. 40g actual physical files on the disk on a fresh install archived as 5g…
John Peterson
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