The cloud is big. Fresh market research from Renub and IDC show exactly how big it is. The analysts found that spending on public and private cloud services will continue to grow rapidly and top $100 billion by 2016.

Renub Research’s “Private Cloud Computing Market & Forecast to 2015: Worldwide Analysis” report shows that application virtualization tools are leading  the private cloud segment and account for 37 percent of the market.  This category is followed by infrastructure and business purpose virtualization. Although middleware virtualization solutions are only a small percent of the market  now, Renub predicts their market share will nearly 10 times their 2011 volume by 2015.

IDC’s numbers focused on the public cloud. It expects the market to grow from  its current size of $40 billion to $100 billion by 2016. IDC expects public cloud services to have an annual compound growth 26.4 percent in the intermediary period, or roughly five times that of the IT industry as a whole. The research firm believes that in the next four years, the public cloud will account for 16 percent of all spending across five of the highest-valued segments: applications, system infrastructure software, and platform as a service (PaaS), servers and basic storage.

“The IT industry is in the midst of an important transformative period as companies invest in the technologies that will drive growth and innovation over the next two to three decades,” Frank Gens, senior vice president and chief analyst at IDC, said in a statement. “By the end of the decade, IDC expects at least 80 percent of the industry’s growth, and enterprises’ highest-value leverage of IT, will be driven by cloud services and the other third-platform technologies.”

Among other things, organizations are also moving their databases to the cloud.  Cost-efficient scalability  coupled with automation is a very attractive combo, and some of the companies that are spearheading this trend has seen a lot of growth lately.