How to choose server for production release of my Django application?

Question

My company is at the very end of development process of some (awesome:)) web application. This app will be available as a online service for (hopefully) some significant number of users. This is our biggest django release so far and as we are preparing to release some question about deployment have to be answered.

Q1: how to determine required server parameters for predicted X number of users/Y hits per minute or other factor?

Q2: what hosting solution (shared/vps/dedicated) is worth considering?

Q3: what optimizations can be done at a first place?

I know that this is very subjective and dependent of size of a site, code quality and other factors but I'm very interested in your experiences with django (and not only django) deployment. Any hints, links, advices are kindly welcome. Thanks in advance.

Answer 1

You can get some guesses here, but to get a halfway reasonable performance estimate you have to measure the performance of your application yourself. You should then be able to roughly extrapolate the performance on different hardware.

Most of the time the bottleneck is the database, you should get enough RAM to keep it in memory if possible.

"Web application" can encompass so many different things, we can really do no more than guess here.

As for optimization, if it fits to your needs implement some caching (e.g. with memchached), that can give you huge speed improvements.

Answer 2

What hosting solution you want to have depends also on how much you want to take of your server yourself (from upgrades etc to backup...), and you should decide if you want to have the responsibility or leave it to someone else.

I think you can only really determine the necessary requirements and bottlenecks in your applications through testing with the estimated load! Try to simulate as many requests.... as you expect - think about caching (where memcached is the best option you have)! If you try to cache things one great tool is the django debug toolbar (http://github.com/robhudson/django-debug-toolbar) which can show you also much about how many database hits you have (dont take the times it shows for that for granted, but analyse them and keep an eye on the number of hits) and eg. how many templates are rendered....

If your system grows, you can first of all think about serving your static media files from another location! Coming to the web server I have made great experiences using lighttpd instead of the fat apache, but I guess you have to evaluate that for yourself! Also take in consideration what database backend to use, in shared envionments there's in most cases a bigger load on the mysql than on the postgres servers, but also evaluate what works best for you!