Qemu-img

qemu-img allows you to create, convert and modify images offline, It can handle all image formats supported by QEMU.

• qemu-img info MY_image-qcow.qcow2
• qemu-img bench

• qemu-img create
  • qemu-img create -f qcow2 MY_IMAGE_NAME.img 3G
  • qemu-img create -f qcow2 -o preallocation=metadata,compat=1.1,lazy_refcounts=on MY_IMAGE_NAME.img

lazy_refcounts=on Reference count updates are postponed with the goal of avoiding metadata I/O and improving performance. Particularly interesting with cache=writethrough.

• Create a snapshot: qemu-img create -f qcow2 -o backing_file=original snapshot.qcow
• qemu-img snapshot (See also: lvcreate --snapshot for LVM snapshots)

• qemu-img convert
• qemu-img check
  • qemu-img check -r all

• qemu-img resize YOUR_IMAGE.qcow2 +SIZE (Extend LVM on qcow2 images) (See also: virsh blockresize)

Activities

• Extend LVM on qcow2 images
• Read qemu-img superuser questions: https://superuser.com/questions/tagged/qemu?tab=Votes

Related commands

• virt-builder
• virt-install

See also

• qemu-img: qemu-img info, qemu-img check, qemu-img resize, qemu-img create, qcow2, qemu-img rebase, qemu-img convert, qemu-img commit, qemu-img ammend
• virtinst (package): virt-install, virt-clone, virt-convert and virt-xml
• QEMU: qemu-img, qemu-ga, qemu.conf, virsh qemu, QEMU guest agent (qemu-ga), qcow2, qemu-nbd, qemu-img map, qemu-io, /etc/libvirt/qemu.conf, QEMU releases, VENOM, qemu-nbd --help, qemu-system
• https://en.wikibooks.org/w/index.php?title=QEMU/Images
• 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

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Source: wikiversity