In the context of Apache Clustering, what needs to happen for data to be replicated among nodes?

For data to be replicated among nodes in the context of Apache Clustering, shared memory configuration is essential. Shared memory allows different nodes in a cluster to access the same data simultaneously, facilitating the synchronization and replication of that data across the nodes. When shared memory is set up, it creates a common data segment that multiple nodes can access, which enhances performance and maintains data consistency.

In scenarios where shared memory is not configured, each node would operate independently, leading to data inconsistency and potential conflicts when nodes try to access or modify the same data. Therefore, shared memory is a critical component that ensures efficient and effective data replication in an Apache Clustering environment.