Clustering is the process of grouping instances of ColdFusion servers for the purposes of redundancy, failover, performance, and load balancing. ColdFusion can be scaled horizontally by increasing ColdFusion instances in a cluster. Session information can be replicated between instances to provide a seamless user experience.
Clustering allows for Sticky Sessions (user sessions stay on a single instance regardless of load) and Session Replication (user session information is copied between all participating instances in the cluster.
In general, ColdFusion clustering is an adequate solution for moderate traffic applications. For extremely high throughput use cases, we advise seeking a hardware solution for load balancing. Load balancing is a CPU bound process, and can limit the processing power available to each instance. In high-performance environments, we advocate single service hardware configurations (each piece of hardware in your infrastructure serves one primary purpose).
We will demonstrate creating a cluster here. Please see Instance Manager for details on creating the two new instances we are clustering here. These operations will be performed from within the cfusion instance.
Enter the new cluster name and click Add. Shown below is the new cluster with no members yet.
Next, we will add the new instances to the cluster. Note that in this example we are Redis to store session variables. Because of this, we do not need to use Sticky Sessions nor Session Replication. Please uncheck those options before saving. The cfusion instance is the instance we are currently using, and will not be added to the cluster (we are clustering two other instances).
The cluster is now ready to accept requests.