Scalability (High Performance) setup is just like high availability setup, the difference is that scalability setup uses Redis as a session storage for SSO. This reduces the I/O and makes possible the horizontal scaling of SSO installations. For instruction on how to install and configure Redis Cluster, please read Redis documentation.
This instruction covers two SSO nodes cluster setup. When installing more SSO nodes the process in still the same → install ldap, install SSO and copy configuration, as in high availability cluster installation.