GNOME Bugzilla – Bug 708836
Generate multiple image types (virtualbox, internal compressed qcow2)
Last modified: 2021-06-05 16:29:32 UTC
The qcow2 format already supports compression, so instead of using gzip on the images one could also do qemu-img convert -O qcow2 -c original-img.qcow2 compressed-img.qcow2 I just tried with the latest image from http://build.gnome.org/ostree/buildmaster/images/z/current/ The resulting file is slightly larger when compared to the gzipped one (421MB vs 438MB) but the good thing is that it can be used directly without uncompressing, so it's easier for the user and takes much less space on their hard drive.
We can do this easily. But note there is a price to this - you pay to decompress blocks on first access. This can substantially increase latency for the first boot, the first time you start an app, etc. OpenStack as I understand it explicitly removes builtin qcow2 compression of uploaded images for this reason. But we can still do it as an additional option perhaps? I'm going to slightly hijack this bug for the purposes of generating multiple images.
(In reply to comment #1) > But note there is a price to this - you pay to decompress blocks on > first access. This can substantially increase latency for the first > boot, the first time you start an app, etc. Sure, I didn't make any measurements :) I just thought that this option hadn't been considered, that's why I proposed it. But if it makes it noticeably slower I'm fine with leaving it as it is now. In my laptop it seems to work just fine FWIW. > But we can still do it as an additional option perhaps? I'm going > to slightly hijack this bug for the purposes of generating multiple > images. My idea was to ship compressed qcow images directly to the end user, I guess people who build their own images are smart enough to do this themselves :)
gnome-continuous is not under active development anymore. Its codebase has been archived: https://gitlab.gnome.org/Archive/gnome-continuous Closing all its open tickets as part of housekeeping.