The global amount of information stored in the year 2012 is expected to reach 2.7 zetta bytes - approx. 48% increase in only one year. One of the most important requirements to store data becomes the scalability and the reliability of a storage system to cope with steadily increasing storage demands.

This presentation is introducing the basic principles, characteristics and fundamental technologies used in the hierarchic model of today's storage systems. In the internet age (people call it web scale) storage systems are shifting from full POSIX compliant systems to more scalable systems with a reduced set of operations like GET, PUT & DELETE - these are so called Cloud Storage Systems with Amazon S3 being the most famous and commonly used storage service. There will be a comparison of both technologies, their advantages and disadvantages and their applicability to various requirements. In particular the technologies used in state of the art large scale systems like Facebook or Google serving hundred millions of users will be explained. This will lead finally to another new trend in storage systems: SaaS (Storage as a Service) and Storage Virtualization.