How scalable is askbot?
Could it run on really large websites, like Stackoverflow..
What are the biggest sites?
It seems that on stackoverflow there are several content writes per minute - in single digits - a single database and an application server will handle that, askbot can do that too - easily.
According to this post (published in March 2011) - http://highscalability.com/blog/2011/3/3/stack-overflow-architecture-update-now-at-95-million-page-vi.html - stackoverflow takes about 100 million pageviews per month - about 40 pageviews per second on average.
Askbot takes 200 ms to generate some pages without caching - that gives only 4 page views per second (on heavy pages, probably 6 if you count in statistics of various page loads). So you'll need 10 read servers working in parallel and one master database server to match performance of stackoverflow with askbot. Possible, but you will need resources and a sys admin.
We are working on serious caching support and the numbers will improve significantly.
Right now I think the pressure from the users is to better support concurrent reads - so we will solve this problem first. For concurrent writes - we'll think of that when some client proves that they actually have that problem.
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