Another Microsoft announcement at BriForum 2007: Longhorn Terminal Services will introduce session-based load balancing.
TS Session Broker, a new feature in Windows Server “Longhorn” Beta 3, provides a simpler alternative than Microsoft Network Load Balancing for Terminal Services. While not limited to a specific number of servers, the feature provides significant value to farms of two to five servers. With TS Session Broker, new sessions are distributed to the least-loaded server within the farm—optimizing performance—and users can reconnect to an existing session without having to know specific information about the server where the session was established. IT managers can use the feature to map the Internet Protocol (IP) address of each terminal server to a single Domain Name System (DNS) entry. This configuration can also provide fault tolerance; if one of the farm servers is unavailable, the user will connect to the next least-loaded server in the farm.
This new load balancing mechanism is not built on NLB. Instead it is built on the TS Session Directory infrastructure.
The way it works in a bit more deail is that when an RDP client connects to a Terminal Server and that server is unable to service that client it queries the Terminal Services Session Broker on that user's behalf and then redirect that client to an alternate server. This redirection happens automatically and does not user interaction. This mechanism also supports server draining - the ability to prevent new sessions from being created on a Terminal Server so that it can be taken offline for maintenance.
So what is not provided? This mechanism is intended to simple scenarios and does not support:
- Application Load Balancing
- Complex/configurable balancing algorithms (built-in support only for session-based load balancing)
for more informaiton on Longhorn Server Features click here
Charles Aunger
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