PrizmDoc Application Services (PAS) is designed to scale out well. By default, it will run multiple threads on a single machine whenever it is capable, and it can be installed to run on multiple machines easily. You will need to do the following in order to run PAS on multiple servers:
You can find out more about configuring PrizmDoc Server with a cloud entry point for a cluster environment in the PrizmDoc Viewer Cluster Mode topic.
Make sure to re-start PAS after every configuration change, in order for the changes to take effect.
There is no special consideration for load balancing several PAS servers. Any request can be routed to any instance of PAS, and you can use any off-the-shelf load balancer to handle the routing.