On Fri, Nov 23, 2018 at 12:43 PM Richard W.M. Jones <rjones(a)redhat.com> wrote:
It looks like the raw format xz-compressed cloud images that we ship
use a very large block size, possibly 192M. This is not ideal and it
would be better to use a smaller block size such as 16M so that they
can be consumed without having to be uncompressed by nbdkit, or even
be used remotely without even downloading them.
(Long story here:
https://rwmj.wordpress.com/2018/11/23/nbdkit-xz-curl/ )
I recompressed the Fedora 29 cloud image using a 16M block size and
there is about 4% overhead to doing this:
before 194278292
after 202874868
At the moment I'm not clear what actual component does the xz
compression step, so I don't even know where I could file a bug or who
I could discuss this with, nor what the current code looks like.
Apparently it's no longer done using appliance-tools.
The cloud images haven't used appliance-tools for years. It uses
imagefactory and some bits in koji.
Looking at the output of the logs it just runs:
$ /usr/bin/xz -z9T2
/var/tmp/koji/tasks/2418/31062418/Fedora-Cloud-Base-Rawhide-20181123.n.0.aarch64.raw
Example task:
https://koji.fedoraproject.org/koji/taskinfo?taskID=31062418
So at a guess it should be a straight forward patch to koji.
Peter