Overview of high availability

High availability is the ability for an application to be accessible with minimal or no downtime, irrespective of various situations that include hardware failure, process crashes due to insufficient resources, memory leaks, maintenance, application upgrade activities, or natural disasters. Pega Platform provides tools to meet high level production service level agreements for mission critical applications with high availability features.

High availability features are available for use with Pega Platform. Any applications built in a version prior to Pega Platform are unable to use high availability features until they are upgraded to a Pega Platform version.

High availability features include:

  • Application server maintenance
    • Operations staff can initiate application tier maintenance that is transparent to users.
    • Pega Platform web application servers that require maintenance can be quiesced.
    • Users on a server that has been quiesced are redirected to other servers in a cluster.
    • Rolling server restarts can be used to upgrade Java Virtual Machine (JVM) settings, physical server maintenance, or Pega Platform upgrades.
  • Application development guidelines
    • System Architects and developers have guidelines to assist them in developing and maintaining highly available Pega Platform applications and strategic applications.
    • Pega Platform System Administrators can control how rules are introduced into the production environment by locking rulesets.
  • Pega Platform updates and upgrades
    • Operations staff can upgrade the Pega Platform without taking production systems offline.
    • Split schema enables administrators to move users on the old rule base to the new rule base with a rolling restart.
  • Network Operation Center integration
    • Operations staff can use Autonomic Event Services (AES) or MBeans to integrate high availability features into their operation centers.
  • Crash recovery
    • Operations staff can rely on application tier crash recovery to recover the user’s work when they log in to other Pega Platform servers in the cluster after a crash.
    • Administrators can optionally notify users that their session has been recovered.
    • Seamless recovery in the event of a browser crash is provided.