QED is an image format (like qcow2, vmdk, etc) that supports backing files and sparse images.
- Base QED is in qemu.git since 2010-12-17 and will form part of QEMU 0.14.
- Merge plan for additional features:
- Zero clusters [submitted].
- Periodic dirty flag flush [submitted].
- Image streaming [in preparation].
- Open specification
- Fully asynchronous I/O path
- Strong data integrity due to simple design
- Backing files
- Backing files may be smaller than the QED image
- Sparse files
- Retains sparseness over non-sparse channels (e.g. HTTP)