Ashish Gujarathi just posted a blog that I think is pivotal for the hosting industry, “Designing a multi-tenant XenApp deployment.” Why is it important? Not because the three models of deployment are so radical – but because most people we talk to have never thought of them as a continuum of non-mutually exclusive options before.

It seems that a term like “multi-tenancy” is as confusing and misunderstood as “virtualization” was (is?!). People have different ideas of what the requirements are, and everything else naturally appears wrong based on your perspective. Ashish does a great job of boiling down multi-tenancy requirements into Isolation, Performance Guarantees, Customized Experience, Self-Service Administration, and Cost, and looking at different deployment models that meet different objectives. He labeled them Shared, Partial Isolation and Full Isolation.

So that got me thinking, what are we seeing in practice amongst hosters?

  • Shared deployment: Today, this is a fairly common model, particularly those offering basic, standard desktop services for SMBs and seeking to aggressively drive down costs/price per subscriber. It provides an adequate level isolation, performance and control for their needs.
  • Full Isolation: At the completely opposite end of the spectrum, this model is best suited for tenants with stringent confidentiality and security requirements, such as federal agencies, healthcare, etc., or heavy duty performance or customization needs. These capabilities come at a cost, however, and CSPs typically are able to charge a premium for this type of service. It is understandably less common to see deployments of this nature – but important to understand that the option exists.
  • Partial Isolation: Many CSPs (and more everyday) are moving to this method, which is facilitated by some of the new architecture of XenApp 6. For most tenants, this model provides arguably the most optimal blend of isolation, performance, customization, self-service admin and cost – which translates into a very competitive price-point. If I’m placing my bets, this will become the prevalent implementation of multi-tenancy in the coming months.

The key point is that all of the above are valid options, and depending on your customer base, you might implement more than one of them. While we expect and encourage CSPs to focus on Partial Isolation for the bulk of tenants, offering other options can broaden their opportunities, allow them to target different segments, and create differentiation.