Lets estimate the volume of tweets. Assume that our system would be the second most popular tweeting service after Twitter.Q: What is the number of users and traffic that we expect the system to handle?
7K new tweets per second. So, write side QPS is 7K. http://www.internetlivestats.com/one-second/#tweets-band
Total new tweets in a day = 500,000000
QPS(Write) = 500,000000/ (24 * 60 * 60) = ~6K (5787)