Package: rsync
Version: 3.1.2-2
Severity: wishlist
Rsync maintains a default list of file extensions that don't benefit from
rsync's own compression:
v3.1.2:loadparm.c:#define DEFAULT_DONT_COMPRESS "*.gz *.zip *.z *.rpm *.deb
*.iso *.bz2" \
v3.1.2:loadparm.c- " *.t[gb]z *.7z *.mp[34] *.mov *.avi *.ogg *.jpg
*.jpeg *.png" \
v3.1.2:loadparm.c- " *.lzo *.rzip *.lzma *.rar *.ace *.gpg *.xz *.txz
*.lz *.tlz"
Please add *.squashfs to this list.
squashfs is sort of a cross between .iso and .tgz, and
is almost always already compressed heavily.
Debian itself uses this format to distribute Debian Live images:
$ rsync --no-motd -hh
mirror.internode.on.net::debian-cd/current-live/amd64/webboot/*.squashfs
-rw-r--r-- 1008.14M 2017/01/17 10:42:11
debian-live-8.7.1-amd64-cinnamon-desktop.squashfs
-rw-r--r-- 1.18G 2017/01/17 10:46:10
debian-live-8.7.1-amd64-gnome-desktop.squashfs
-rw-r--r-- 1.08G 2017/01/17 10:43:35
debian-live-8.7.1-amd64-kde-desktop.squashfs
-rw-r--r-- 843.36M 2017/01/17 10:33:24
debian-live-8.7.1-amd64-lxde-desktop.squashfs
-rw-r--r-- 878.48M 2017/01/17 10:33:10
debian-live-8.7.1-amd64-mate-desktop.squashfs
-rw-r--r-- 302.14M 2017/01/17 10:15:36
debian-live-8.7.1-amd64-standard.squashfs
-rw-r--r-- 837.21M 2017/01/17 10:33:16
debian-live-8.7.1-amd64-xfce-desktop.squashfs
The default can be overridden in rsyncd.conf (dont compress = ...) or with
rsync (--skip-compress=...),
so this is not urgent, just "nice to have".
It looks like this list hasn't changed since 2010.
You might want to add some other extensions that have appeared in the latest
decade --- ogv, webm, webp spring to mind.
