Have already scraped Amazon millions product many time. I have various server machine. I run them with large set of proxy and high letency. So I can complete 1 millions within 5 days.
these are my skills set related to web scraping
Have done scraping in Nodejs, CasperJS Phantomjs, python.
Have done testing and automation with selenium also.
Know to deal with database like mongo, mysql, Elasticsearch.
Also know to handle proxy and captcha while scrapping.