The tool used for simulating cluster conditions on a single machine for testing is the MiniCluster. It allows developers to test their Hadoop applications in a controlled environment, simulating the behavior of a Hadoop cluster on a local machine for ease of debugging and testing.

The feature of YARN that helps in improving the scalability of the Hadoop ecosystem is Horizontal Scalability. YARN allows for the addition of more nodes to the cluster, providing horizontal scalability and the ability to handle larger workloads efficiently.

Sqoop achieves high throughput in data transfer using the Direct Mode, which allows direct communication between the Sqoop client and the database, bypassing the need for intermediate storage in Hadoop. This results in faster data transfers with reduced latency.

To optimize data processing, Hash partitioning in Hadoop can significantly improve the performance of MapReduce jobs. Hash partitioning ensures that related data is grouped together, reducing the amount of data shuffled between nodes during the MapReduce process and improving overall performance.

Hadoop clusters use Block Replication to optimize data storage and access. Data is replicated across multiple nodes to ensure data availability and fault tolerance, allowing for efficient data retrieval and processing.

Parquet is the preferred file format for large-scale data processing in Hadoop due to its columnar storage, compression techniques, and schema evolution support. It offers high performance for analytical queries and is well-suited for data warehouse applications.

When a file in HDFS is smaller than the Hadoop block size, padding is applied. The file does not occupy the entire block, and the remaining space is padded with zeros. This approach ensures uniformity in block size, simplifying data management and storage.

Apache Flume's architecture supports distributed data collection through an agent-based model. Agents are responsible for collecting, aggregating, and transporting data across the distributed environment. This approach enables flexibility and scalability in handling diverse data sources and destinations.

The correct option is 'SLA (Service Level Agreement).' In advanced Oozie workflows, SLA is used to manage job retries and error handling. It provides a mechanism to define and enforce performance expectations for various jobs within the workflow.

The module in Apache Spark specifically designed for SQL and structured data processing is Spark SQL. It provides a programming interface for data manipulation using SQL queries, enabling users to seamlessly integrate SQL queries with Spark applications.

The Fairness of a Hadoop cluster indicates the balance of load across its nodes. It ensures that each node receives a fair share of tasks, preventing resource imbalance and improving overall cluster efficiency.

Apache Oozie integrates with other Hadoop ecosystem components, such as Hive and Pig, through Action Nodes. These nodes define specific tasks, such as MapReduce, Pig, or Hive jobs, and orchestrate their execution as part of the workflow.