To configure an AOS instance as a batch server go to System Administration > Setup > System and open Server Configuration form. Select the AOS instance to configure from the grid on the left. Check Is batch server to specify this instance as a batch server. Expand the fast tab Batch Server Schedule. Mention the Maximum batch threads along with start and end times.
Please note that maximum batch threads only controls how many concurrent threads will be running on this instance. You can create as many threads as you like in x++. For example, maximum batch threads is set to 20 and your x++ code is creating 30 threads to perform a job. In this case, first 20 out of 30 threads will be running concurrently while the remaining 10 threads will be in the waiting state till the first 20 threads finish their job.
You can specify multiple maximum batch threads and bind them to specific time slots using Start time and End time. In this way we can configure the same AOS instance to allow different maximum batch threads in different time slots. For example, in rush hours we can specify more concurrent threads as compared to idle hours!
Feel free to comment in case of any questions!