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qemu-img[1] allows you to create, convert and modify images offline, It can handle all image formats supported by QEMU.

  • 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[3]

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

Activities[edit | edit source]

See also[edit | edit source]

  1. https://manpages.debian.org/testing/qemu-utils/qemu-img.1.en.html
  2. https://manpages.debian.org/testing/qemu-utils/qemu-img.1.en.html
  3. http://libguestfs.org/virt-sysprep.1.html#copying-and-cloning
  4. https://maunium.net/blog/resizing-qcow2-images/
  5. https://serverfault.com/questions/324281/how-do-you-increase-a-kvm-guests-disk-space