Like “Web 2.0”, the term “Cloud computing” is one that nobody much likes, but is hard to avoid. Argue all you like; but there are real and significant changes, and we need to call it something.
I wrote a piece in today’s Guardian which looks at some of the issues. Tony Lucas at Flexiscale, a cloud computing provider, makes the point that “occasional large outages are actually more likely than small ones”. His words were prophetic; I spoke to him shortly before Flexiscale itself went offline for two days. That’s unacceptable for anything business-critical; there has to be a plan B. SLAs by the way are not the answer; they promise some level of compensation in the event of failure, but this is typically miniscule in comparison to the business consequences.
Virtualization could be the answer. If your virtual servers at one provider go offline, just bring them up with another provider. That implies interoperability; and if this interests you, note that Amazon’s Jeff Barr is speaking on this subject with Lucas at the Future of Web Apps conference in London next month. Another development is VMware’s vCloud, which promises to “federate between on-premise and off-premise clouds” with its vServices. VMware is also a big supporter of the Open Virtual Machine Format (OVF), a format for portable virtual machines. If the reliability problem is solved, it will remove a key barrier to adoption of this kind of on-demand computing.