Krzysztof Lichota wrote the following on 17.12.2007 13:05 recently i also tried 7z for my backups and in comparation to bz2 it seems to take a bit longer during compressing but is faster on extraction. Also the compressed file with 7z is ~30% compared to a bz2 one.
</snip> > It is hard to judge best compression using only one package. It is > possible that for other packages other compression schemes would be > better. Have you run built other packages? ?The best would be to rebuild > whole repo with new compression scheme and compare the results, so that > it does not appear, for example, that packages stop fitting into one CD. atached is a more detailed analysis trying to compare gz, bz2 and 7z (aka LZMA). I tried it once for (mostly) textfiles as source and once on a binary file in both compressing and extraction. </snip> > Krzysztof Lichota HTH -- Thilo key: 0x4A411E09
compressing binary =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= $ which tarbz2 tarbz2 is aliased to `/bin/tar --bzip2 -cvpf' $ which targz targz is aliased to `/bin/tar -cvzpf' $ du --max-depth=1 -k openoffice.org-core_1%3a2.3.0-1ubuntu5.3_i386.deb 36996 openoffice.org-core_1%3a2.3.0-1ubuntu5.3_i386.deb $ time tarbz2 oo.tar.bz2 openoffice.org-core_1%3a2.3.0-1ubuntu5.3_i386.deb real 0m19.243s user 0m18.761s sys 0m0.156s $ ls -lk oo.tar.bz2 -rw------- 1 USER USER 36931 17.12.2007 15:23 oo.tar.bz2 $ time tar cf - openoffice.org-core_1%3a2.3.0-1ubuntu5.3_i386.deb | 7za a -si oo.tar.7z real 0m32.141s user 0m30.506s sys 0m0.312s $ ls -lk oo.tar.7z -rw------- 1 USER USER 37014 17.12.2007 15:24 oo.tar.7z $ time tar cf - openoffice.org-core_1%3a2.3.0-1ubuntu5.3_i386.deb | 7za a -si -m0=lzma oo-lzma.tar.7z real 0m31.555s user 0m30.762s sys 0m0.324s $ ls -lk oo-lzma.tar.7z -rw------- 1 USER USER 37014 17.12.2007 15:27 oo-lzma.tar.7z $ time targz oo.tar.gz openoffice.org-core_1%3a2.3.0-1ubuntu5.3_i386.deb real 0m3.316s user 0m2.988s sys 0m0.140s $ ls -lk oo.tar.gz -rw------- 1 USER USER 36723 17.12.2007 15:29 oo.tar.gz extracting binary =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= $ which untarbz2 untarbz2 is aliased to `/bin/tar --bzip2 -xvpf' $ which untargz untargz is aliased to `/bin/tar -xvzpf' $ time untarbz2 oo.tar.bz2 real 0m8.522s user 0m8.205s sys 0m0.232s $ ls -lk open* -rw------- 1 USER USER 36951 17.12.2007 15:20 openoffice.org-core_1%3a2.3.0-1ubuntu5.3_i386.deb $ time untargz oo.tar.gz real 0m0.636s user 0m0.484s sys 0m0.128s $ ls -lk open* -rw------- 1 USER USER 36951 17.12.2007 15:20 openoffice.org-core_1%3a2.3.0-1ubuntu5.3_i386.deb $ time 7za x -so oo.tar.7z | tar xf - real 0m5.849s user 0m5.616s sys 0m0.176s $ ls -lk open* -rw------- 1 USER USER 36951 17.12.2007 15:20 openoffice.org-core_1%3a2.3.0-1ubuntu5.3_i386.deb
compressing mostly textfiles =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= $ which tarbz2 tarbz2 is aliased to `/bin/tar --bzip2 -cvpf' $ which targz targz is aliased to `/bin/tar -cvzpf' $ du --max-depth=1 -k | grep delta 108444 ./delta $ time tarbz2 delta.tar.bz2 delta/ real 0m48.591s user 0m38.234s sys 0m0.524s $ ls -lk delta.tar.bz2 -rw------- 1 USER USER 65152 17.12.2007 14:48 delta.tar.bz2 $ time tar cf - delta/ | 7za a -si delta.tar.7z real 1m1.577s user 0m59.928s sys 0m0.448s $ ls -lk delta.tar.7z -rw------- 1 USER USER 13977 17.12.2007 14:56 delta.tar.7z $ time tar cf - delta/ | 7za a -si -m0=lzma delta-lzma.tar.7z real 1m1.268s user 0m59.936s sys 0m0.404s $ ls -lk delta-lzma.tar.7z -rw------- 1 USER USER 13977 17.12.2007 14:58 delta-lzma.tar.7z $ time targz delta.tar.gz delta/ real 0m11.449s user 0m10.213s sys 0m0.292s $ ls -lk delta.tar.gz -rw------- 1 USER USER 66371 17.12.2007 14:59 delta.tar.gz extracting mostly textfiles =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= $ which untarbz2 untarbz2 is aliased to `/bin/tar --bzip2 -xvpf' $ which untargz untargz is aliased to `/bin/tar -xvzpf' $ time untarbz2 delta.tar.bz2 real 0m20.017s user 0m18.173s sys 0m0.824s $ du --max-depth=1 -k 108444 ./delta $ time untargz delta.tar.gz real 0m8.205s user 0m1.856s sys 0m0.420s $ du --max-depth=1 -k 108444 ./delta $ time 7za x -so delta.tar.7z | tar xf - real 0m5.030s user 0m3.136s sys 0m0.452s $ du --max-depth=1 -k 108444 ./delta
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