Creating a highly available system typically requires coordination across multiple groups in an organization. Individuals or groups responsible for deploying highly available systems must collectively understand and agree on how to configure the Pega Platform for their organization.
The smallest environment for basic configuration testing requires the following:
- A load balancer
- Two instances of a web application platform of choice
- A database backend
- A shared disk for shared storage
Additionally, as a part of planning for future server maintenance, you must decide whether to use the default immeditate drain method or configure your system to instead use the slow drain method when you perform the quiesce process on a node. For more information, see Quiescing high availability nodes.
- Understanding system settings for high availability environments
There are multiple ways to set and manage Pega Platform settings. Following are recommended methods listed in terms of precedence:
- Setting up load balancers
User and service requests are passed through a load balancer to the Pega Platform servers. The Pega Platform server in turn makes requests to a database.
- Configuring session affinity for slow drain
Session affinity is configured with the load balancer. Session affinity ensures that all requests from a user are handled by the same Pega Platform server.
- Configuring application tier architecture for redundancy
Highly available application tier architectures must have enough computing power to support fail-over, as well as a means to allocate new servers to support increased demands for service.