bad news for bsdtar..

[Julian Elischer]

done on a small subdirectory of our data...
(only accounts starting with 849xxx)
total data as reported by 'du': 9394486 KB  (9GB)
(note du takes links into account and doesn't count the same data twice)
number of files with > 1 link: 
# find 849* -type f -links +1 | wc -l
  240395
#
total number of file directory entries..
# find 849* -type f | wc -l
  598018
#
total number of directories:
%find 849* -type d | wc -l
   51245

average filesize 23k
but major file types are: jpeg images.. 100kb
			jpeg thumbnails, 3kb
			transaction descriptors 1kb
########################################################
the bad news:

old (FreeBSD 2.x) tar with symlink hack
%time ~/tar cf /dev/null 849*
5.309u 73.584s 21:15.44 6.1%    329+5150k 786697+0io 0pf+0w

freebsd 4.8 tar
%time tar cf /dev/null 849
5.159u 17.724s 4:08.97 9.1%     364+5863k 66144+0io 1pf+0w

bsdtar
%time ~/bsdtar cf /dev/null 849*
16.423u 68.141s 31:40.82 4.4%   402+1639k 784651+0io 0pf+0w

It looks to me that the tar in 4.8 is doing something very
sneeky with it's IOs..
maybe using mmap?
maybe detecting /dev/null and instead discarding the data?
maybe reading the entire file in a single read?