How many servers for Office Web Apps

Question

I'm looking for how many servers to add for OWA. I need it highly available for around 4,000 concurrent users. I'm assuming I only need 2 but not sure if I need more or not. SharePoint 2013 with around 15,000 users all together

Answer 1

Yes should be ok with 2 servers (one could probably do, but you need redundancy anyway), unless the documents your users are editing are extremely long or usage scenarios are extremely heavy (for example you stop deploying local office client, but I would advise against it - what I can see from practice OWA is used by users main for viewing when they need to edit they switch to local word or excel app)

This article is great intro to OWA\WAC server in v2013

Answer 2

For high availability, you need the at least the 2 servers behind a load balancer.

Capacity mainly depends upon how to use the application. i.e. what ype of operation you want allow edit or view only, how many users, what is expected response time etc.

Check this planning document