tool

rsync (with faster line) without --delete (to keep deleted *.tgz)
wget  (with limited band-width, the same as regular user's)

Adding perl script: 
generate-a-list (pkgsrc and daily) --> *.html
ftp://ftp.jp.netbsd.org/pub/NetBSD-jp/mirror-status/release/HEAD.html

expire (for daily only) --> rm -rf