Load balancing with mod_cluster
mod_cluster is an HTTP-based load balancer that can be used to forward a request to a set of application server instances. Compared to legacy balancing solutions balancing solutions such as mod_jk or mod_proxy, mod_cluster provides the following benefits:
Dynamic balancing configuration
Pluggable server-side balancing metrics
As far as the first point is concerned, a load balancer is commonly based on a static list of servers where requests are directed. In many cases this can be a limiting factor especially when server nodes can be varied at runtime; besides this, maintaining a static list of servers is error-prone and needs to reshaped every time there is a change in your network.
About the next point, mod_cluster (in contrast to other frontend based balancers) uses load balance factors calculated and provided by the backend application servers, rather than computing these in the proxy. Consequently, mod_cluster offers a more robust and accurate set of load...
