Unit 1: Introduction to Hadoop - Practice Quiz

1 What does the term Big Data generally describe?

2 Which activity commonly generates large volumes of data?

3 Why are traditional data-processing tools sometimes unsuitable for Big Data?

4 Which type of data follows a fixed schema with rows and columns?

5 Which is an example of unstructured data?

6 Which is an example of semi-structured data?

7 Which V of Big Data refers to the amount of data generated and stored?

8 Which V of Big Data describes the speed at which data is generated and processed?

9 Which V of Big Data refers to the different formats and sources of data?

10 Which V of Big Data is concerned with data accuracy and trustworthiness?

11 What is Apache Hadoop primarily designed to do?

12 Apache Hadoop is best described as which type of software?

13 Which feature allows Hadoop to increase capacity by adding more computers to a cluster?

14 Which Hadoop component provides distributed storage?

15 Which Hadoop component manages cluster resources and schedules applications?

16 Which Hadoop component processes data using map and reduce tasks?

17 What does the NameNode manage in HDFS?

18 Which software platform must be installed before running Apache Hadoop?

19 Which environment variable commonly identifies the Java installation directory during Hadoop setup?

20 Which Hadoop command is commonly used to verify that Hadoop is installed and display its version?

21 An online marketplace generates several terabytes of clickstream data each day. A single database server cannot process the data within the required time. Which capability is most appropriate for this problem?

22 A company stores customer transactions efficiently in a relational database, but its recommendation system must also analyze images, reviews, and browsing events. Why is a Big Data approach appropriate?

23 A bank must choose which workload to move from its transaction system to a Big Data platform. Which workload is the best candidate?

24 A data pipeline receives fixed-schema sales tables, JSON application events, and product photographs. How should these sources be classified, respectively?

25 A log file contains one JSON object per line, but different events may contain different fields. Which data type best describes the file?

26 A hospital wants to combine relational patient records with free-text physician notes. Which statement best describes the integration challenge?

27 A fraud-detection system must evaluate thousands of card events per second before approving transactions. Which V of Big Data is the primary concern?

28 Weather sensors occasionally report impossible temperatures because of faulty calibration. Which V should the data engineering team address first?

29 An analytics platform must process database rows, audio recordings, XML documents, and social media images. Which V is most directly illustrated?

30 A retailer stores petabytes of customer activity but has not identified any decisions that the data can improve. Which V is currently least realized?

31 In an HDFS cluster with replication enabled, one worker machine fails during a batch analysis. Why can the Hadoop job usually continue?

32 A Hadoop cluster is running out of storage and processing capacity. Which action best follows Hadoop's typical scaling model?

33 Which workload is most suitable for a standard Hadoop batch-processing environment?

34 A client needs to locate the DataNodes containing the blocks of an HDFS file. Which component provides the required metadata?

35 A YARN application requests cluster resources, but the central service responsible for allocating containers is unavailable. Which component has failed?

36 In a MapReduce job, mappers emit (customerID, purchaseAmount) pairs. What normally happens before reducers calculate totals for each customer?

37 An administrator expects the SecondaryNameNode to become the active NameNode automatically after a failure. Why is this expectation incorrect in a basic Hadoop setup?

38 After installing Hadoop, running hadoop version reports that Java cannot be found even though Java is installed. Which configuration should be checked first?

39 An administrator is initializing a new pseudo-distributed HDFS installation for the first time. Which command prepares the NameNode's storage metadata?

40 When start-dfs.sh is executed in a pseudo-distributed installation, the script repeatedly asks for the local user's password. What is the most appropriate fix?

41 A company receives only 800 GB of new data per day, but its centralized database cannot ingest the data within the required time window or economically scale to support analysis. Which conclusion is most accurate?

42 An application stores events as JSON documents. Different events may contain different optional attributes, but each document uses keys and nested structures. How should this data be classified?

43 A machine-learning repository contains JPEG images, JSON annotation documents, and label records in relational tables. Which classification correctly describes the individual components?

44 A streaming system receives millions of events per second, but network delays cause some events to arrive several minutes after later events. Which Big Data characteristic most directly drives the need for windowing and late-event handling?

45 Two trusted medical data providers report conflicting values for the same patient's test result, and neither value can immediately be validated. Which V is the primary concern?

46 An organization stores petabytes of logs and processes them reliably, but no team can identify a decision, service, or measurable outcome improved by the analysis. Which V remains least satisfied?

47 Which workload is least aligned with Hadoop's traditional design strengths?

48 A large HDFS file has replicas on several worker nodes. When scheduling a map task for one block, which placement generally minimizes network traffic?

49 A client can list HDFS file names and permissions, but attempts to read file contents fail because all DataNodes are unavailable. What best explains this behavior?

50 An HDFS file has replication factor 3, and rack-aware placement has put its replicas across two racks. One entire rack becomes unavailable, while the other retains one replica. What is the immediate file state?

51 Ignoring the final partial-block case, a GiB file is stored in HDFS using a MiB block size and replication factor 3. How many physical block replicas are stored?

52 In YARN, which component pairing correctly separates cluster-wide resource arbitration from per-application task coordination?

53 A MapReduce job computes the average transaction value for each customer. Which combiner output design is safe when the combiner may run zero, one, or multiple times?

54 A MapReduce job uses the default hash partitioner and multiple reducers. Which ordering guarantee is valid after the shuffle and sort phase?

55 Which design supports automatic HDFS NameNode failover while keeping the standby NameNode's namespace state synchronized?

56 A cluster stores ten million files of 2 KB each, far below the configured HDFS block size. Storage capacity remains available, but NameNode memory becomes a bottleneck. What is the main cause?

57 One machine runs the NameNode, DataNode, ResourceManager, and NodeManager as separate Java processes, and HDFS is configured with replication factor 1. Which Hadoop deployment mode is this?

58 A host is omitted from Hadoop's workers file, but its DataNode is started manually with the correct fs.defaultFS and network configuration. What is the most accurate outcome?

59 Hadoop commands work in an administrator's interactive shell, but daemons launched remotely by start-dfs.sh fail with a Java-not-found error. Which correction is most appropriate?

60 After copying a preconfigured DataNode data directory to several new workers, only one worker registers successfully; the others are rejected as duplicate DataNodes. What is the safest corrective action?