Scale-Out File Server is a feature that is designed to provide scale-out file shares that are continuously available for file-based server application storage. Scale-out file shares provides the ability to share the same folder from multiple nodes of the same cluster. This scenario focuses on how to plan for and deploy Scale-Out File Server.

With scale-out file shares, you can share the same folder from multiple nodes of a cluster. For instance, if you have a four-node file server cluster that is using Server Message Block (SMB) Scale-Out, a computer running Windows Server 2012 R2 or Windows Server 2012 can access file shares from any of the four nodes. This is achieved by leveraging new Windows Server Failover Clustering features and the capabilities of the Windows file server protocol, SMB 3.0. File server administrators can provide scale-out file shares and continuously available file services to server applications and respond to increased demands quickly by simply bringing more servers online. All of this can be done in a production environment, and it is completely transparent to the server application.

Information sourced from http://technet.microsoft.com/en-gb/library/hh831349.aspx