What scale-out roles can be assigned to hosts in the nameserver.ini file?

When configuring the scale-out roles for hosts in the nameserver.ini file, it is essential to understand the responsibilities each role has within the architecture of the High-Performance Analytic Appliance (HANA).

The STANDBY role is designed for hosts that provide redundancy and high availability to the system. When assigned this role, the STANDBY instance stays in sync with the active instance and can take over if the active instance fails, ensuring continued service availability without data loss. This is especially critical in systems where uptime is vital, as it allows for failover without manual intervention.

In contrast, the WORKER role is assigned to hosts that actually execute the workload, processing data and performing calculations. The MASTER role refers to the host that coordinates the activities of worker nodes and holds metadata, while the CLIENT role pertains to connections made from client applications to the HANA system but does not provide any hosting functions or workload executions.

In the context of the question, the correct option focuses on the specific purpose of hosts in the nameserver.ini configuration file where the STANDBY role is explicitly allocated for failover support, thereby playing a critical part in maintaining system resilience and service continuity.