It’s hard to get a answer. But I am always thanking about this question. The people who use open source may not announce to the wold “we are running apache+tomcat as on-line banking service!!!”. As far as I know, more and more peoples going to choice open source software whenever they have this option.
Let’s narrow down this question. That will be more interesting.
Senior Developer Relations/Advocate, Founder of DevOps China, Microsoft MVP