Another question from someone I work with. “Can you explain the meaning of ‘Multi-Tenant’? Aren’t all virtualized servers and storage ‘Multi-Tenant’?”
The term Multi-Tenant is a little misleading. Technically, yes virtualized servers are multi-tenant in that there are multiple servers running on a single server. The term Multi-Tenant in the technology world however typically refers to a system where more than one company is using the same systems.
By way of example, we can look at a cloud hosting provider such as HP’s Cloud System Matrix (CSM). As a disclaimer, this not an official HP Blog, and I am not an expert on CSM, but I do have a solid understanding of it. So on CSM, you have multiple options. The most common and cost effective method is to simply purchase a virtual instance of a server. Essentially you get a virtual machine. Your virtual machine is on the same physical machine as several other peoples. In fact, it might get moved to other servers using vMotion without your knowledge. The concept is that you are simply renting or leasing a virtual machine, but you don’t care what the physical hardware is.
In the HP StoreServ, formerly 3Par, storage, arena, we have a similar concept of multi-tenancy. Consider the design of the 3Par array. Everything within the system is built first for redundancy, then for performance. It is the only truly tier 1 array that extends from the SMB through the global enterprise using the same architecture. The system was originally designed for hosting providers, thus everything had to remain functional no matter what. With this in mind, the system was created to be multi-tenant. It is literally possible to present the system as multiple virtual SAN’s without the users realizing it. This is perfect again if you want a granular control of your SAN, but you want to rent or lease it. A service provider might purchase a large system, and partition it off to many different companies. Since they all share the SAN, the system in multi-tenant. The HP StoreServ array is able to give a secure virtual san to each user.
So to wrap up, something which is virtualized but not multi-tenant would be most traditional virtualized systems. A company virtualizes their infrastructure within their own datacenter, or even at a colo. Since they are the only company on the system, that would be a single tenant system, or not-multi-tenant.