For over a decade, the load balancer has played a major role in Microsoft Exchange deployments. Like the prior versions, Exchange 2019 requires a load balancer to provide the availability for the Client Access Services running on the Mailbox Servers. In this release, Microsoft focused on performance and security rather than many new features and functionality. LoadMaster’s Intelligent traffic distribution and Edge Security Pack further enhance these core areas delivered in Exchange 2019. Layer 7 is still the recommended method leveraging the load balancer’s advanced health checking capabilities.
- A client session connects to the Exchange namespace virtual IP address (VIP) on the load balancer
- The client session is redirected by the load balancer to an available mailbox server in the load balanced pool
- The mailbox server authenticates the request and performs service discovery
- The mailbox server may proxy or redirect the request to another mailbox server hosting the active copy
The Office Online Server (OOS), which is required to provide uniform document preview and editing in OWA, is not supported for co-location with Exchange 2019. This means that the Office Online Server farm will require its own namespace with session affinity being maintained by the Kemp LoadMaster load balancer. In a multi-datacentre environment, global server load balancing (GSLB) is recommended to deliver an Exchange 2019 environment in a single namespace.