Introduction to RHEL High Availability with Pacemaker In the database layer, you can set up native database replication between primary and secondary databases to ensure high availability. For high availability of ASCS, use Enqueue Replication Server (ERS) to replicate the lock table entries. Isolate the crash by removing the application server from the load balancer. If an application server crashes, only the users connected to that server are impacted. You can implement high availability for application servers by using a load balancer and having multiple application servers handle the requests from users. High Availability in Application and Database Layers
Interactive course: Getting started with OpenShift.O'Reilly: Kubernetes patterns for designing cloud-native apps.The Enqueue Server controls the lock mechanism. The Message Server acts as a communication channel between all the application servers and handles the distribution of the load. The central services comprise two main components-Message Server (MS) and Enqueue Server (ES). Another main component in the application layer is the ABAP SAP Central Service (ASCS). Based on the system requirement, multiple application servers are created to handle the load on the SAP system. Application server instances provide the actual data processing functions of an SAP system. In this article, the main focus is on the application layer. Database layer-Contains the database with all SAP related data (for example, Oracle).Application layer-Contains one or more application servers and a message server.Presentation layer-Presents a GUI for interaction with the SAP application.
In this article, I discuss how to leverage Red Hat Enterprise Linux (RHEL) Pacemaker for High Availability (HA) of SAP NetWeaver Advanced Business Application Programming (ABAP) SAP Central Service (ASCS)/Enqueue Replication Server (ERS).
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