Cluster Magento Website

We currently have two servers for this site of which magento version is 1.9.0.1: 1. Frontend Server (Linode, Managed by Serverpilot Coach Account, might not be a good idea to simply clone the server): Contains: magento frontend, 2 wordpress sites served as sub-directories, 4 Mysql Database: 2 for the wordpress sites, 1 for self-hosted live chat, 1 for redis 2. Dedicated Database Server (hosts magento mysql database only). Due to the recent frequent outages and the needs of a server in west coast. We'd like to add two more servers (1 frontend server & database server - slave or backup server in case the master server is down...) We would like to use a node balance to redirect traffic to their closest server, but sessions or cookies (we do have WAF service from [login to view URL] and it can do the balaning function.)