How many default Backgrounder instances are established unless the core count is fewer than 8?

The correct answer is based on understanding the architecture of Tableau Server and its default settings for handling background tasks. When the core count of Tableau Server nodes is 8 or more, Tableau establishes 2 default Backgrounder instances to manage scheduled tasks and data extracts efficiently. This design is intended to optimize performance and ensure that background tasks do not impede the user experience by allowing them to run in parallel across multiple processes.

Backgrounders are responsible for running tasks like refreshing data extracts and subscribing to views, which can be resource-intensive. By having 2 instances, Tableau can spread the workload, reducing the time it takes for background tasks to complete and preventing bottlenecks that could occur if only one instance were handling all tasks.

If the core count were fewer than 8, Tableau Server would adjust its resources accordingly and typically configure only a single Backgrounder instance. This allows for efficient resource utilization while still handling the necessary background tasks without overwhelming the server, but it limits the parallel processing capability due to the reduced number of cores available.

Understanding this scaling mechanism is key for administrators to ensure their Tableau Server environment runs efficiently, particularly when managing larger datasets or higher user demand.