Speaking about backend in Celery, I recommend to use memcached or Redis. Please, do not use database. When I started using task queue I tend to use database as a backend very often due to several reasons: it is very easy to set up; django-celery supports it very good; no additional dependency. read more
A new article by Deni Bertovic on this topic was just posted to Hacker News. read more
Celery - Best Practices. If you've worked with Django at some point you probably had the need for some background processing of long running tasks. Chances are you've used some sort of task queue, and Celery is currently the most popular project for this sort of thing in the Python (and Django) world (but there are others). read more