Am 27.06.2017 um 15:20 schrieb Daniel P. Berrange:
On Tue, Jun 27, 2017 at 02:34:07PM +0200, Peter Lieven wrote:
this patch adds a new compression_algorithm option when creating qcow2 images.
The current default for the compresison algorithm is zlib and zlib will be
used when this option is omitted (like before).
If the option is specified e.g. with:
qemu-img create -f qcow2 -o compression_algorithm=zlib image.qcow2 1G
IMHO we should introduce a nested struct "compress" struct to hold the format
name, and any other format specific arguments, in a way that maps nicely to
any future QAPI representmatch of create options. eg
{ 'enum': 'BlockdevQcow2CompressFormat',
'data': [ 'zlib', 'lzo' ] }
{ 'union': 'BlockdevQcow2Compress',
'base': { 'format': 'BlockdevQcow2CompressFormat' },
'discriminator': 'format',
'data': { 'zlib': 'BlockdevQcow2CompressZLib',
'lzo': 'BlockdevQcow2CompressLZO'} }
so it would map to
qemu-img create -f qcow2 -o compress.format=zlib image.qcow2 1G
and let us have other compress.XXXX options specific to each format
Or would it be possible to start with just a compress.level (int) parameter.
In fact that would be sufficient for almost all formats (or better use
algorithms?).
The windowBits can be default to -15 in the future. It seems the old choice of
-12
was just not optimal. We just have to use it for backwards compatiblity if the
compress
options are not specified.
Peter
