pax versus tar

ahmedb72 · 08-22-2007, 03:44 AM

Hi all,

I'm trying to compare performance of tar and pax utilities. I noticed that pax files are much more in size than tar files. Actually pax files are larger in size than the files contained in the archive file.

Here is what I tried:

Code:

bash-3.00# ls -lh
total 527322
drwxr-xr-x  76 root     root        4.0K Aug 20 23:27 dir1
-rw-r--r--   1 root     root        252M Aug 21 21:55 dir1.pax
drwxr-xr-x   2 root     root         512 Aug 20 23:27 dir2
-rw-r--r--   1 ahmed    root         136 Aug 19 01:37 local.cshrc
-rw-r--r--   1 ahmed    root         157 Aug 19 01:37 local.login
-rw-r--r--   1 ahmed    root         213 Aug 19 01:44 local.profile
-rw------T   1 root     root        5.0M Aug 19 20:59 opening.avi
-rw-r--r--   1 root     root         12K Aug 21 21:55 whos.txt
bash-3.00# rm dir1.pax
bash-3.00# ls
dir1           local.cshrc    local.profile  whos.txt
dir2           local.login    opening.avi
bash-3.00# ls -l
total 10298
drwxr-xr-x  76 root     root        4096 Aug 20 23:27 dir1
drwxr-xr-x   2 root     root         512 Aug 20 23:27 dir2
-rw-r--r--   1 ahmed    root         136 Aug 19 01:37 local.cshrc
-rw-r--r--   1 ahmed    root         157 Aug 19 01:37 local.login
-rw-r--r--   1 ahmed    root         213 Aug 19 01:44 local.profile
-rw------T   1 root     root     5242880 Aug 19 20:59 opening.avi
-rw-r--r--   1 root     root       12855 Aug 21 21:57 whos.txt
bash-3.00# tar cf dir1.tar dir1
bash-3.00# find ./dir1 -print | pax -w -f dir1.pax
bash-3.00# ls -ldh dir*
drwxr-xr-x  76 root     root        4.0K Aug 20 23:27 dir1
-rw-r--r--   1 root     root        252M Aug 21 21:58 dir1.pax
-rw-r--r--   1 root     root         49M Aug 21 21:57 dir1.tar
drwxr-xr-x   2 root     root         512 Aug 20 23:27 dir2

jlliagre · 08-22-2007, 05:56 AM

I suppose dir1 has many small or zero size files for such a difference to appear. In that case, you certainly can efficiently compress the archive if size is an issue.