We are looking to load balance our IPS forum and I am somewhat stuck on how to move forward. My issue is that I am not sure how to sync the files between the servers. We could use rsync but it seems that would be super complicated to use for bidirectional syncs. I also thought about NFS but that introduces a single point of failure from that network share. Does any have recommendations on how to sync files bidirectionally, or how you do sync files? 

If you use S3 for file storage and enable database for your datastore there's really not much that has to sync between servers. The only time it would write is if you do things with plugins, apps, and of course upgrades.

@Charles Applications and plugins are mostly what I was worried about. But do they normally use the upload folder for plugins?

Applications use /applications and plugins use /plugins.