If you believe the vendors' advertising claims, all the problems relating to cloud - whether private, public or hybrid - have long been solved. What the vendors are deliberately concealing is the fact that effective cost savings and efficiency increases require a paradigm shift. As usual, there is quite a discrepancy between vendor promises and reality. A conversation with Ivan Pepelnjak, one of the world's top experts in networking, data center, cloud and scalable application design, to get a realistic assessment.