The recommended approach is to utilize the unbounded model, deploying a single Exchange namespace per client protocol for the site resilient datacenter pair (where each datacenter is assumed to represent its own Active Directory site - see more details on that below). For the namespace, the choices are to either deploy a bound namespace (having a preference for the users to operate out of a specific datacenter) or an unbound namespace (having the users connect to any datacenter without preference). In the Namespace Planning and Load Balancing Principles articles, I outlined the various configuration choices that are available with Exchange 2016. The PA is divided into four areas of focus: The PA removes complexity and redundancy where necessary to drive the architecture to a predictable recovery model: when a failure occurs, another copy of the affected database is activated. Alternatively, you can consider Office 365 where you can take advantage of the PA without having to deploy or manage servers. If you fall into those categories, and you want to deploy Exchange on-premises, there are still advantages to adhering as closely as possible to the PA, and deviate only where your requirements widely differ.
And some of our customers have different business requirements or other needs which necessitate a different architecture. The specific prescriptive nature of the PA means of course that not every customer will be able to deploy it (for example, customers without multiple datacenters). Increase availability by optimizing around failure domains and reducing complexity.Reduce the cost of the messaging infrastructure.Support multiple copies of each database, thereby allowing for quick activation.Include both high availability within the datacenter, and site resilience between datacenters.The PA is designed with several business requirements in mind, such as the requirement that the architecture be able to: While there are other supported deployment architectures, they are not recommended. While Exchange 2016 offers a wide variety of architectural choices for on-premises deployments, the architecture discussed below is our most scrutinized one ever. The Preferred Architecture (PA) is the Exchange Engineering Team’s best practice recommendation for what we believe is the optimum deployment architecture for Exchange 2016, and one that is very similar to what we deploy in Office 365.