Latest 100 Best Hadoop (Bigdata) Interview Questions and Answers for freshers and experienced pdf
1. What is BIG DATA?
2. Can you give some examples of Big Data?
3. Can you give a detailed overview about the Big Data being generated by Facebook?
4. According to IBM, what are the three characteristics of Big Data?
5. How Big is ‘Big Data’?
6. How analysis of Big Data is useful for organizations?
7. Who are ‘Data Scientists’?
8. What is Hadoop?
9. Why the name ‘Hadoop’?
10. Why do we need Hadoop?
11. What are some of the characteristics of Hadoop framework?
12. Give a brief overview of Hadoop history.
13. Give examples of some companies that are using Hadoop structure?
14. What is the basic difference between traditional RDBMS and Hadoop?
15. What is structured and unstructured data?
16. What are the core components of Hadoop?
17. What is HDFS?
18. What are the key features of HDFS?
19. What is Fault Tolerance?
20. Replication causes data redundancy then why is pursued in HDFS?
21. Since the data is replicated thrice in HDFS, does it mean that any calculation done on one node will also be replicated on the other two?
22. What is throughput? How does HDFS get a good throughput?
23. What is streaming access?
24. What is a commodity hardware? Does commodity hardware include RAM?
25. What is a Namenode?
26. Is Namenode also a commodity?
27. What is a metadata?
28. What is a Datanode?
29. Why do we use HDFS for applications having large data sets and not when there are lot of small files?
30. What is a daemon?
31. What is a job tracker?
32. What is a task tracker?
33. Is Namenode machine same as datanode machine as in terms of hardware?
34. What is a heartbeat in HDFS?
35. Are Namenode and job tracker on the same host?
36. What is a ‘block’ in HDFS?
37. If a particular file is 50 mb, will the HDFS block still consume 64 mb as the default size?
38. What are the benefits of block transfer?
39. If we want to copy 10 blocks from one machine to another, but another machine can copy only 8.5 blocks, can the blocks be broken at the time of replication?
40. How indexing is done in HDFS?
41. If a data Node is full how it’s identified?
42. If datanodes increase, then do we need to upgrade Namenode?
43. Are job tracker and task trackers present in separate machines?
44. When we send a data to a node, do we allow settling in time, before sending another data to that node?
45. Does hadoop always require digital data to process?
46. On what basis Namenode will decide which datanode to write on?
47. Doesn’t Google have its very own version of DFS?
48. Who is a ‘user’ in HDFS?
49. Is client the end user in HDFS?
50. What is the communication channel between client and namenode/datanode?
51. What is a rack?
52. On what basis data will be stored on a rack?
53. Do we need to place 2nd and 3rd data in rack 2 only?
54. What if rack 2 and datanode fails?
55. What is a Secondary Namenode? Is it a substitute to the Namenode?
56. What is the difference between Gen1 and Gen2 Hadoop with regards to the Namenode?
57. What is MapReduce?
58. Can you explain how do ‘map’ and ‘reduce’ work?
59. What is ‘Key value pair’ in HDFS?
60. What is the difference between MapReduce engine and HDFS cluster?
61. Is map like a pointer?
62. Do we require two servers for the Namenode and the datanodes?
63. Why are the number of splits equal to the number of maps?
64. Is a job split into maps?
65. Which are the two types of ‘writes’ in HDFS?
66. Why ‘Reading‘ is done in parallel and ‘Writing‘ is not in HDFS?
67. Can Hadoop be compared to NOSQL database like Cassandra?
68. What is MapReduce?
69. What are ‘maps’ and ‘reduces’?
70. What are the four basic parameters of a mapper?
71. What are the four basic parameters of a reducer?
72. What do the master class and the output class do?
73. What is the input type/format in MapReduce by default?
74. Is it mandatory to set input and output type/format in MapReduce?
75. What does the text input format do?
76. What does job conf class do?
77. What does conf.setMapper Class do?
78. What do sorting and shuffling do?
79. What does a split do?
80. What does a MapReduce partitioner do?
81. How is Hadoop different from other data processing tools?
82. Can we rename the output file?
83. Why we cannot do aggregation (addition) in a mapper? Why we require reducer for that?
84. What is Streaming?
85. What is a Combiner?
86. What is the difference between an HDFS Block and Input Split?
87. What happens in a textinputformat?
88. What do you know about keyvaluetextinputformat?
89. What do you know about Sequencefileinputformat?
90. What do you know about Nlineoutputformat?
91. Which are the three modes in which Hadoop can be run?
92. What are the features of Stand alone (local) mode?
93. What are the features of Pseudo mode?
94. Can we call VMs as pseudos?
95. What are the features of Fully Distributed mode?
96. Does Hadoop follows the UNIX pattern?
97. In which directory Hadoop is installed?
98. What are the port numbers of Namenode, job tracker and task tracker?
99. What is the Hadoop-core configuration?
100.What are the Hadoop configuration files at present?
1. What is BIG DATA?
2. Can you give some examples of Big Data?
3. Can you give a detailed overview about the Big Data being generated by Facebook?
4. According to IBM, what are the three characteristics of Big Data?
5. How Big is ‘Big Data’?
6. How analysis of Big Data is useful for organizations?
7. Who are ‘Data Scientists’?
8. What is Hadoop?
9. Why the name ‘Hadoop’?
10. Why do we need Hadoop?
11. What are some of the characteristics of Hadoop framework?
12. Give a brief overview of Hadoop history.
13. Give examples of some companies that are using Hadoop structure?
14. What is the basic difference between traditional RDBMS and Hadoop?
15. What is structured and unstructured data?
16. What are the core components of Hadoop?
17. What is HDFS?
18. What are the key features of HDFS?
19. What is Fault Tolerance?
20. Replication causes data redundancy then why is pursued in HDFS?
21. Since the data is replicated thrice in HDFS, does it mean that any calculation done on one node will also be replicated on the other two?
22. What is throughput? How does HDFS get a good throughput?
23. What is streaming access?
24. What is a commodity hardware? Does commodity hardware include RAM?
25. What is a Namenode?
26. Is Namenode also a commodity?
27. What is a metadata?
28. What is a Datanode?
29. Why do we use HDFS for applications having large data sets and not when there are lot of small files?
30. What is a daemon?
31. What is a job tracker?
32. What is a task tracker?
33. Is Namenode machine same as datanode machine as in terms of hardware?
34. What is a heartbeat in HDFS?
35. Are Namenode and job tracker on the same host?
36. What is a ‘block’ in HDFS?
37. If a particular file is 50 mb, will the HDFS block still consume 64 mb as the default size?
38. What are the benefits of block transfer?
39. If we want to copy 10 blocks from one machine to another, but another machine can copy only 8.5 blocks, can the blocks be broken at the time of replication?
40. How indexing is done in HDFS?
41. If a data Node is full how it’s identified?
42. If datanodes increase, then do we need to upgrade Namenode?
43. Are job tracker and task trackers present in separate machines?
44. When we send a data to a node, do we allow settling in time, before sending another data to that node?
45. Does hadoop always require digital data to process?
46. On what basis Namenode will decide which datanode to write on?
47. Doesn’t Google have its very own version of DFS?
48. Who is a ‘user’ in HDFS?
49. Is client the end user in HDFS?
50. What is the communication channel between client and namenode/datanode?
51. What is a rack?
52. On what basis data will be stored on a rack?
53. Do we need to place 2nd and 3rd data in rack 2 only?
54. What if rack 2 and datanode fails?
55. What is a Secondary Namenode? Is it a substitute to the Namenode?
56. What is the difference between Gen1 and Gen2 Hadoop with regards to the Namenode?
57. What is MapReduce?
58. Can you explain how do ‘map’ and ‘reduce’ work?
59. What is ‘Key value pair’ in HDFS?
60. What is the difference between MapReduce engine and HDFS cluster?
61. Is map like a pointer?
62. Do we require two servers for the Namenode and the datanodes?
63. Why are the number of splits equal to the number of maps?
64. Is a job split into maps?
65. Which are the two types of ‘writes’ in HDFS?
66. Why ‘Reading‘ is done in parallel and ‘Writing‘ is not in HDFS?
67. Can Hadoop be compared to NOSQL database like Cassandra?
68. What is MapReduce?
69. What are ‘maps’ and ‘reduces’?
70. What are the four basic parameters of a mapper?
71. What are the four basic parameters of a reducer?
72. What do the master class and the output class do?
73. What is the input type/format in MapReduce by default?
74. Is it mandatory to set input and output type/format in MapReduce?
75. What does the text input format do?
76. What does job conf class do?
77. What does conf.setMapper Class do?
78. What do sorting and shuffling do?
79. What does a split do?
80. What does a MapReduce partitioner do?
81. How is Hadoop different from other data processing tools?
82. Can we rename the output file?
83. Why we cannot do aggregation (addition) in a mapper? Why we require reducer for that?
84. What is Streaming?
85. What is a Combiner?
86. What is the difference between an HDFS Block and Input Split?
87. What happens in a textinputformat?
88. What do you know about keyvaluetextinputformat?
89. What do you know about Sequencefileinputformat?
90. What do you know about Nlineoutputformat?
91. Which are the three modes in which Hadoop can be run?
92. What are the features of Stand alone (local) mode?
93. What are the features of Pseudo mode?
94. Can we call VMs as pseudos?
95. What are the features of Fully Distributed mode?
96. Does Hadoop follows the UNIX pattern?
97. In which directory Hadoop is installed?
98. What are the port numbers of Namenode, job tracker and task tracker?
99. What is the Hadoop-core configuration?
100.What are the Hadoop configuration files at present?
