Configuring a multi-server WordPress environment

First let me start by saying I’m new to WordPress but have been around IT for 30 years.

We are getting ready to deploy a WordPress site (migrated a .Net site to WordPress). We are strongly considering AWS with a configuration that potentially includes 2 Web servers (load balanced) and a single MySQL DB server. We want redundancy built into the website as it is the cornerstone for obtaiining client orders.

Are there any issues with configuring multiple servers for a WordPress environment? Does anyone else have any other suggestions for building in realtime redundancy to insure 99.9999 uptime?

Thanks in advance, Jeff