How to organize load balancing between two pools in IIS 7 (win2008)?

Question

IIS

Problem: when updating the site, some functions do not work, heavy database queries are detected. It is necessary to provide constant access of users to the service.
Due to regular problems during site updates, the idea arose to organize a balancing between the active project and the test project (for example, give 10% of requests to the test one).
In theory, if you have nginx and store sessions in the database, this could be done. But there is no such intermediate server now and will not be expected.
Question: is it possible to organize balancing without using another server directly in win2008?

Answer 1

Look towards ARR
It is not obligatory to store sessions in a DB.
1) ARR seems to allow you to bind a session to a backend
2) You can use the State Server to store sessions, but you need to be careful (it can lower performance) and not when you want 10% of users, but when you just want to wind up the number of processes more than one pool