celery and its use of kombu have some configuration. For example
kombu can use redis instead of mongodb. It would be good, if we had
some documentation on how to setup celery in some different ways.
Using redis as a backend db (will likely be better, except it needs
yet another daemon running) could be a nice example case in the
documentation.

mongodb needs 0.5 GB for a fresh install. Half of this goes to
kombu.

kombu could use redis or some other transport (see
`#322 </issues/322>`_), so fixing `#322 </issues/322>`_ will help
this issue too.

mongodb database files contain a lot of NUL bytes. So one can
easily use sparse files to save space on disk:

::

     # service mongodb stop
     # cd /var/lib/
     # cp -a --sparse=always mongodb mongodb.new
     # mv mongodb mongodb.old
     # mv mongodb.new mongodb
     # service mongodb start
     # # TEST mongodb
     # rm -rf mongodb.old

Maybe later versions of mongodb do this already internally. The
above was needed on mongodb from debian/stable.

Documenting the "make sparse" possibility will also help this
issue.

Currently you can try to upload a html file.

What happens currebtly? It sticks in the queue, because celery goes
crazy on it.
The good news: It does not end up in a public place.

What should NEVER, ever happen: The file being put in a public
place. It's the best XSS attack to come up with.

Rating this high, because this needs to be right for security
reasons.