[Mageia-dev] [ANN] unbloated installer stage1

Tue Jan 24 22:03:06 CET 2012

Den 13:09 24. januar 2012 skrev Thierry Vignaud
+<thierry.vignaud at gmail.com> følgende:
+> Hi
+>
+> Over the years, stage1 (both  all.rdz, boot.iso, ...) got bigger & bigger:
+> 10.0-10.1: 8Mo
+> 10.2-2005: 15M      <=======
+> 2006.0: 13M
+> 2007.0: 14M
+> 2007.1: 10M
+> 2008.0-2008.1: 12M
+> 2009.0: 26M      <=======
+> 2009.1: 32M      <=======
+> 2010.0: 33M
+> 2010.1: 36M (37M on 64 bit)
+> 2011   : 44M
+> mga1  : 39M (40M on 64bit) (NEW: 53M on non-free 64 bit...)
+>
+> I've reduced this by:
+> - removing alt1 (x86_64 only for now):
+> - removing busybox
+> - compressing initrd with XZ instead of gzip: only good on firmware
+> - re compressing kernel modules with XZ instead of gzip:
+lzma supports much bigger dictionaries than zlib, so in stead of
+compressing the kernel modules individually, you'd achieve much better
+compression by just letting them be compressed once as part
+of the initrd as they'd all share one big dictionary. :)
+lzma also has several options you may tune to improve compression even
+further.
+>
+> Removing alt1 (x86_64 only for now) saved 20Mb on boot.iso (50%)
+> and on boot-nonfree.iso (43%).
+>
+> Removing busybox saved 1B (5.7% of all.rdz, 5% of boot.iso,
+> 3.7% of boot-nonfree.iso)
+Why not replace all the programs possible with busybox alternatives
+and link everything against uClibc rather than glibc?
+>
+> Compressing initrd with XZ instead of gzip saved 2Mo (7.7%) on
+> boot-nonfree.iso (better compressed firmwares).
+avoiding compression of any individual files (not just kernel modules) and just
+compress them all together once will help increase compression ratio.
+>
+> Re-compressing kernel modules with XZ instead of gzip saved -2.4Mb (15.9%)
+> on all.rdz, -2Mb (10.5%) on boot.iso, -2mb on boot-nonfree.iso (8.3%)
+>
+> Total gain on boot.iso: -23Mb (57.5%) on x86_64 (less on i586)
+>
+> This should save space on ISOs too (we could save more by
+> not including install/images on ISOs btw)
+>
+> There's a minor drawback: KA install won't work anymore but
+> it's a niche. Is there someone using that feature?
+> The proper way to support it would be to either:
+> - have a stage1.5 for KA with busybox
+> - include a static mke2fs (compiled against dietlibc)
+compile everything against shared uClibc libraries in stead! :)
+There might also be a gain in using the new x32abi introduced in
+latest kernels..
+> - disable KA support
+
+To give an example, by applying these "tricks" to mkinitrd in the
+past, I managed
+to reduce it's size all the way down to just below 1MB (which also
+added a full-featured
+busybox build for rescue environment, going further and using a
+minimal busybox build
+and dropping plymouth I managed to push it further down to 100KB! :).
+
+--
+Regards,
+Per Øyvind
+