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

• qemu-img resize YOUR_IMAGE.qcow2 +SIZE (KVM/Extend LVM on qcow2 images)

• qemu-img snapshot (See also: lvcreate --snapshot for LVM snapshots)

Activities

• KVM/Extend LVM on qcow2 images

See also

• virt-install python script
• virt-manager
• https://en.wikibooks.org/w/index.php?title=QEMU/Images