> I was just going to write about this. I have just turned on gnutar
> backups. I noticed that the estimates are basically tar operations with
> all of the ouput going to /dev/null. That is what's taking the time.
> Not to get the file's size, but to move the date through that system
> pipe into /dev/null.
GNU tar knows about /dev/null and how to handle it:
# time tar cf /dev/null /usr
tar: Removing leading `/' from member names
tar: Removing leading `/' from link names
6.40user 31.16system 2:10.64elapsed 28%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (188major+94minor)pagefaults 0swaps
# time tar cf - /usr | cat > /dev/null
tar: Removing leading `/' from member names
tar: Removing leading `/' from link names
7.81user 53.46system 10:44.20elapsed 9%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (348major+158minor)pagefaults 0swaps
# time tar cf - /usr | cat > /dev/null
tar: Removing leading `/' from member names
tar: Removing leading `/' from link names
7.70user 53.33system 10:33.26elapsed 9%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (325major+153minor)pagefaults 0swaps
# time tar cf /dev/null /usr
tar: Removing leading `/' from member names
tar: Removing leading `/' from link names
6.12user 29.42system 2:04.54elapsed 28%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (188major+94minor)pagefaults 0swaps
# tar --version
tar (GNU tar) 1.13.17
Copyright 2000 Free Software Foundation, Inc.
This program comes with NO WARRANTY, to the extent permitted by law.
You may redistribute it under the terms of the GNU General Public
License;
see the file named COPYING for details.
Written by John Gilmore and Jay Fenlason.
