On Mon, Jul 15, 2013 at 01:06:26PM +0200, Lukas Zapletal wrote:
On Mon, Jul 15, 2013 at 12:22:22PM +0200, Jaroslav Reznik wrote:
> downloadable cloud images (in qcow2 and raw.xz format) produced and released
I know that it is convenient to expose qcow2 images uncompressed so
users are able to upload them directly into clouds via httpd. Qcow2 is
compressed already by default (is that zlib?) so I am wondering if there
Just for clarity, qcow2 can be compressed or uncompressed; these are
compressed.
is any way of re-compressing the image with "-9" option so
we are sure
the size is the best we can offer.
I think this may just come down to deflate (zlib) vs lzma (xz). A comment in
the qemu-img source code says "best compression, small window, no zlib
header" -- I'm kind of guessing, but I expect that the small window size was
chosen on purpose for when the image is actually used.
Currently qemu-img does not offer that. Size comparison between qcow2
vs
raw.xz shows that there are most likely some gaps we can fill in the
qcow2 size.
Just throwing in some ideas. Maybe not that relevant for this, I
apologize.
Probably not relevant, but I'm open for any approaches for improvement.
--
Matthew Miller ☁☁☁ Fedora Cloud Architect ☁☁☁ <mattdm(a)fedoraproject.org>