On Fri, Sep 01, 2023 at 12:24:30PM +0200, Kevin Wolf wrote: > Document the 'compression_type' option for qcow2, and mention that > streamOptimized vmdk supports compression, too. > > Reported-by: Richard W.M. Jones <[email protected]> > Signed-off-by: Kevin Wolf <[email protected]>
Looks good, so: Reviewed-by: Richard W.M. Jones <[email protected]> > --- > docs/tools/qemu-img.rst | 19 +++++++++++++++++-- > 1 file changed, 17 insertions(+), 2 deletions(-) > > diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst > index 15aeddc6d8..ca5a2773cf 100644 > --- a/docs/tools/qemu-img.rst > +++ b/docs/tools/qemu-img.rst > @@ -106,7 +106,11 @@ by the used format or see the format descriptions below > for details. > > .. option:: -c > > - Indicates that target image must be compressed (qcow format only). > + Indicates that target image must be compressed (qcow/qcow2 and vmdk with > + streamOptimized subformat only). > + > + For qcow2, the compression algorithm can be specified with the ``-o > + compression_type=...`` option (see below). > > .. option:: -h > > @@ -776,7 +780,7 @@ Supported image file formats: > > QEMU image format, the most versatile format. Use it to have smaller > images (useful if your filesystem does not supports holes, for example > - on Windows), optional AES encryption, zlib based compression and > + on Windows), optional AES encryption, zlib or zstd based compression and > support of multiple VM snapshots. > > Supported options: > @@ -794,6 +798,17 @@ Supported image file formats: > ``backing_fmt`` > Image format of the base image > > + ``compression_type`` > + This option configures which compression algorithm will be used for > + compressed clusters on the image. Note that setting this option doesn't > yet > + cause the image to actually receive compressed writes. It is most > commonly > + used with the ``-c`` option of ``qemu-img convert``, but can also be used > + with the ``compress`` filter driver or backup block jobs with compression > + enabled. > + > + Valid values are ``zlib`` and ``zstd``. For images that use > + ``compat=0.10``, only ``zlib`` compression is available. > + > ``encryption`` > If this option is set to ``on``, the image is encrypted with > 128-bit AES-CBC. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com libguestfs lets you edit virtual machines. Supports shell scripting, bindings from many languages. http://libguestfs.org
