Change to bzip2?
Phil Knirsch
pknirsch at redhat.com
Wed Feb 2 17:09:49 UTC 2005
Paul Iadonisi wrote:
>
> [snip]
>
> Which begs the question ... why has Red Hat (at least in some cases,
> historically), veered (admittedly only slightly) from the pristine
> source principle by uncompressing gzipped tarballs and recompressing
> them with bzip2 only to stuff them in into an rpm if rpm uses gzip?
>
I think that compressing tarballs of source tars in srpms is a little
different than compressing the payload in binary rpms.
Because for the first you don't actually need the least itsybitsy of
speed and using bzip2 safes quite a bit of storage for source tarballs.
For binary rpms otoh it's different as there you want a quick
installation, so uncompression speed does matter there, and the
difference for the binary payload compress with bzip2 and gzip should be
considerably less drastic than with source tarballs.
As a test i've created a cpio archive of the current openoffice package
in FC:
[root at hamburg tmp]# ll foo.cpio
-rw-r--r-- 1 root root 98993152 Feb 2 17:51 foo.cpio
Now the different runtimes and sizes for gzip:
[root at hamburg tmp]# /usr/bin/time gzip -9 foo.cpio
20.15user 0.31system 0:20.47elapsed 99%CPU
[root at hamburg tmp]# ll foo.cpio.gz
-rw-r--r-- 1 root root 34026424 Feb 2 17:51 foo.cpio.gz
[root at hamburg tmp]# /usr/bin/time gunzip -9 foo.cpio.gz
1.19user 0.37system 0:01.65elapsed 94%CPU
Now the same for bzip2:
[root at hamburg tmp]# /usr/bin/time bzip2 -9 foo.cpio
52.49user 0.45system 0:53.05elapsed 99%CPU
[root at hamburg tmp]# ll foo.cpio.bz2
-rw-r--r-- 1 root root 30408374 Feb 2 17:51 foo.cpio.bz2
[root at hamburg tmp]# /usr/bin/time bunzip2 foo.cpio.bz2
11.73user 0.69system 0:12.47elapsed 99%CPU
So the speed difference in unpacking is about 1:10, size difference is
about 1.12:1 which clearly demonstrates my point. I don't want my
installation to take 10 times longer for the sake of 12% space saving in
the binary rpms.
My uncompressed $0.02
Read ya, Phil
--
Philipp Knirsch | Tel.: +49-711-96437-470
Development | Fax.: +49-711-96437-111
Red Hat GmbH | Email: Phil Knirsch <phil at redhat.de>
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Motd: You're only jealous cos the little penguins are talking to me.
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