Deleting files is way slower than creating them.
I wonder if the creation order matters: if files are in a SHA pattern it's horrible!
- http://askubuntu.com/questions/114969/is-there-any-faster-way-to-remove-a-directory-than-rm-rf
- http://serverfault.com/questions/128012/how-to-make-rm-faster-on-ext3-linux
- http://serverfault.com/questions/183821/rm-on-a-directory-with-millions-of-files/328305#328305
- http://stackoverflow.com/questions/1795370/unix-fast-remove-directory-for-cleaning-up-daily-builds
- http://superuser.com/questions/680119/deleting-millions-of-files
- http://unix.stackexchange.com/questions/37329/efficiently-delete-large-directory-containing-thousands-of-files