I was confused by Oracle CEO Larry Elison's comments during the Oracle Public Cloud keynote at OpenWorld 2011 which refered to salesforce.com's multitenant cloud as old technology and then referred to virtualization technology as newer, strongly implying that it is more advanced and a better solution.
The salesforce.com platform has had multitenancy for years, but that is not a weakness. Many cloud platforms are still trying to add the capability to seamlessly host multiple applications securely. So good on Oracle to try and use salesforce.com's strength as a weakness, however it has to be pointed out that saying the sky is green does not make it true.
As to ranking technology by age and saying that the oldest concept loses, I'll just bring up virtualization on mainframes and leave it at that.
Oracle's implication that a platform with multitenancy built-in is inferior to a design based on multiple virtualized single tenant platforms is just not true. All modern systems have, or at least should have, security implemented at some level of the technology stack and there are pros and cons of having the security higher up in the application platform, near the middle in the OS or hypervisor or at the bottom near the sectors of the storage device. All these options can be made secure if security was considered when the design was created.
Security was the highest design priority for salesforce.com. It is implemented at multiple layers in its platform (from individual database records to fields in the user interface) because the platform was designed with multitenancy in mind from the start.
In contrast designs based on virtualized operating systems running single tenant platforms can certainly be made secure if you take care to ensure every tenant gets a virtualized copy of every layer of your stack but unless multitenant security is built into the application development platform, like it is with salesforce.com, I would consider it a less secure architecture.
To summarize I feel that having security build into an application platform is a key requirement for a cloud platform whether or not the platform is hosted on virtualized operating systems, storage and networks.
Cheers,
Mark
