[Ovirt-devel] Appliance disk format

[Jim Meyering]

"Daniel P. Berrange" <berrange at redhat.com> wrote:
...
> To see if there's any further compression to be had for helping downloads
> I tried various compression programs with the following results:
>
>   - gzip  - 661M
>   - bzip2 - 662M
>   - p7zip - 617M
>   - rzip  - 586M
>
> All used their default compression levels. rzip is pretty impressive, and
> p7zip is not too shabby. It is clearly not worth using gzip/bzip though.

Neat.  If you want maximum compression, you probably don't want to use
the default level.

For maximum compression, try lzma with its -9 option.
  [yum install lzma  aka http://tukaani.org/lzma/ ]
But with such a big file, it'll take a long time.
Though maybe it's worth it...
On some quick tests, lzma -9 produced a file 15% smaller
than rzip -9 did.

Note that p7zip is more of an archiving program, like tar.
p7zip can use LZMA for compression.
The lzma program is more like gzip and bzip2.