svn commit: r264027 - in head: release share/man/man7

[Glen Barber]

On Wed, Apr 02, 2014 at 12:23:46PM -0400, Nikolai Lifanov wrote:
> On 04/02/14 12:06, Glen Barber wrote:
> > On Wed, Apr 02, 2014 at 11:55:33AM -0400, Nikolai Lifanov wrote:
> >> On 04/02/14 11:51, Glen Barber wrote:
> >>> On Wed, Apr 02, 2014 at 10:40:22AM -0500, Brooks Davis wrote:
> >>>> On Tue, Apr 01, 2014 at 10:41:27PM +0000, Glen Barber wrote:
> >>>>> Author: gjb
> >>>>> Date: Tue Apr  1 22:41:26 2014
> >>>>> New Revision: 264027
> >>>>> URL: http://svnweb.freebsd.org/changeset/base/264027
> >>>>>
> >>>>> Log:
> >>>>>   Add a new release build variable, WITH_COMPRESSED_IMAGES.
> >>>>>   
> >>>>>   When set to a non-empty value, the installation medium is
> >>>>>   compressed with gzip(1) as part of the 'install' target in
> >>>>>   the release/ directory.
> >>>>>   
> >>>>>   With gzip(1) compression, downloadable image are reduced in
> >>>>>   size quite significantly.  Build test against head at 263927
> >>>>>   shows the following:
> >>>>>   
> >>>>>    bootonly.iso:		64% smaller
> >>>>>    disc1.iso:		44% smaller
> >>>>>    memstick.img:		47% smaller
> >>>>>    mini-memstick.img:	65% smaller
> >>>>>    dvd1.iso:		untested
> >>>>>   
> >>>>>   This option is off by default, I would eventually like to
> >>>>>   turn it on by default, and remove the '-k' flag to gzip(1)
> >>>>>   so only compressed images are published on FTP.
> >>>>
> >>>> I'd recommend testing xz compression as well.  With UFS images of a full
> >>>> world the savings vs gzip are significant (more than 30% IIRC, but it's
> >>>> need more than a year since I checked so I'm a bit unsure of the exact
> >>>> numbers).
> >>>>
> >>>
> >>> delphij also brought this up.
> >>>
> >>> I have concerns with xz(1), since there was mention in IRC that Windows
> >>> users may have problems decompressing xz-compressed images.  So, gzip(1)
> >>> is used because it seems to be the more commonly-supported archive
> >>> mechanisms.
> >>>
> >>> The benefit of xz(1) over gzip(1) was only 50M-ish.
> >>>
> >>>   -rw-r--r--  1 root  wheel   601M Mar 28 20:18 disc1.iso
> >>>   -rw-r--r--  1 root  wheel   381M Mar 28 20:18 disc1.iso.bz2
> >>>   -rw-r--r--  1 root  wheel   392M Mar 28 20:18 disc1.iso.gz
> >>>   -rw-r--r--  1 root  wheel   348M Mar 28 20:18 disc1.iso.xz
> >>>
> >>> Glen
> >>>
> >>
> >> How about 7zip (Windows program, not file format)? What would a Windows
> >> user use that can decompress gzip and not xz? It was a problem around
> >> ~2007, but xz support is no longer rare or exotic.
> >>
> > 
> > I don't know, to be honest.  I have no Windows machines to test, so
> > I can only go by what I am told.
> > 
> > Glen
> > 
> 
> I just verified it with 7zip for Windows version 9.22. It extracts
> .tar.xz archives and decompresses .xz images.
> 

Great, thank you for confirming.

So, the question I have now is, considering the time it takes to
compress the image with xz(1) compared to gzip(1), is that worth saving
the 50MB space?

I do not object to using xz(1), but the compression time difference was
quite significant.  (I do not have numbers off-hand, but can run the
compression again.)

Glen

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