Denis Plotnikov <dplotni...@virtuozzo.com> writes: > The patch adds some preparation parts for incompatible compression type > feature to QCOW2 header that indicates that *all* compressed clusters > must be (de)compressed using a certain compression type. > > It is implied that the compression type is set on the image creation and > can be changed only later by image conversion, thus compression type > defines the only compression algorithm used for the image. > > The goal of the feature is to add support of other compression algorithms > to qcow2. For example, ZSTD which is more effective on compression than ZLIB. > It works roughly 2x faster than ZLIB providing a comparable compression ratio > and therefore provide a performance advantage in backup scenarios. > > The default compression is ZLIB. Images created with ZLIB compression type > are backward compatible with older qemu versions. > > Signed-off-by: Denis Plotnikov <dplotni...@virtuozzo.com>
QAPI schema Acked-by: Markus Armbruster <arm...@redhat.com>
