The requirements for the Rendering Service are different according to installation type.
Baseline Hardware Requirements for Single- or Multiple-Node Unblu Cluster Setup. Note that the resources required for the rendering service are listed, in the table(s), as a 'part' of the entire system. Also see Cluster Hardware Requirements Typical Setup.
The rendering service is an option and only required if you want to be able to browse anywhere on the Web and/or if you want to be able to co-browse PDFs. (You can share almost any type of document via upload/download without the Rendering Service.)
The rendering service method of co-browsing means an entire new browser is created, inside the server, when a universal session is started (including co-browsing a document).
This means the rendering service is relatively expensive, in terms of compute resources. Each and every session will consume a lot of resources. Therefore, whatever your method of running unblu, the rendering service is treated as a separate requirement.
Bear in mind that *the rendering service is only required when:*
You want to co-browse Web pages that are not instrumented to run Unblu (they have no unblu snippet in the code). For example, you want to browse competitor pages or news stories, or perhaps you want to just browse together to figure out an investment idea.
you want to co-browse PDF documents. Virtually any type of document can still be uploaded/downloaded from both Agent and Visitor sides without the rendering service but you would not be able to co-browse them.
If you find that relationship managers, for example, feel that co-browsing documents and/or other Web sites is advantageous to their goals, it is simple to add more compute. In general, this is how your system may evolve. The actual usage will dictate the allocation of resources. Nothing is wasted. The vast majority of your Agents' time will be spent browsing your own resources. It may be that 'high-value' visitors require the rendering service from time to time as it provides a seamless portal to the entire Web as well as a highly-intimate and targeted method of sharing your documents.