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Question 1
You have one primary HMaster and one standby. Your primary HMaster Falls fails and your client application needs to make a metadata change. Which of the following is the effect on your client application?
A. The client will query ZooKeeper to find the location of the new HMaster and complete the metadata
B. The client will make the metadata change regardless of the slate of the HMaster. C. The new HMaster will notify the client and complete the metadata change.
D. The client application will fail with a runtime error.
Answer A
Question 2
You have an average key-value pair size of 100 bytes. Your primary access is random needs on the table. Which of the following actions will speed up random reading performance on your cluster?
A. Turn off WAL on puts
B. Increase the number of versions kept C. Decrease the block size
D. Increase the block size

Cloudera CCB-400
Answer D
Question 3
The cells in a given row have versions that range from 1000 to 2000. You execute a delete specifying the value 3000 for the version. What is the outcome?
A. The delete fails with an error.
B. Only cells equal to the Specified version are deleted. C. The entire row is deleted.
D. Nothing in the row is deleted.
Answer C
Reference: (scroll below and see Delete topic, read the last paragraph)
Question 4
You have an "Employees" table in HBase. The Row Keys are the employees' IDs. You would like to retrieve all employees who have an employee ID between 'user_100' and 'user_110'. The shell command you would use to complete this is:
A. scan 'Employees', {STARTROW => 'user_100', STOPROW => 'user_111'} B. get 'Employees', {STARTROW => 'user_100', STOPROW => 'user_110'} C. scan 'Employees', {STARTROW => 'user_100', SLIMIT => 10}
D. scan 'Employees', {STARTROW => 'user_100', STOPROW => 'user_110'}
Answer D
Question 5
Under default settings, which feature of HBase ensures that data won't be lost in the event of a RegionServer failure?
A. All HBase activity is written to the WAL, which is stored in HDFS B. All operations are logged on the HMaster.
C. HBase is ACID compliant, which guarantees that it is Durable.

Cloudera CCB-400
D. Data is stored on the local filesystem of the RegionServer.
Answer A Explanation:
Reference: (See 'From the post' second paragraph)
Question 6
You have two standbys and one primary HMaster. Your primary HMaster fails. Which of the remaining HMasters becomes the new primary?
A. Whichever HMaster first responds to ZooKeeper B. Whichever HMaster ZooKeeper randomly selects C. Whichever HMaster creates the znode first
D. Whichever HMaster has the lower IP address
Answer A
Question 7
Data is written to the HLog in which of the following orders? A. In order of writes
B. In order of writes, separated by region
C. Ascending first by region and second by row key
D. Descending first by region and second by row key
Answer D
Question 8
You have a table with the following rowkeys:
r1, r2, r3, r10, r15, r20, r25, r30, r35
In which order will these rows be retrieved from a scan?
A. r35, r30, r3, r25, r20, r2, r15, r10, r1 B. r1, r2, r3, r10, r15, r20, r25, r30, r35 C. r1, r10, r15, r2, r20, r25, r3, r30, r35

Cloudera CCB-400
D. r35, r30, r25, r20, r15, r10, r3, r2, r1
Answer D
Question 9
You need to create a "WebLogs" table in HBase. The table will consist of a single Column Family called "Errors" and two column qualifiers, "IP" and "URL". The shell command you should use to create the table is:
A. create 'WebLogs', {NAME => 'Errors:IP', NAME =>'Errors:URL'}
B. create 'WebLogs', 'Errors' {NAME => 'IP', NAME => 'URL'}
C. create 'WebLogs', 'Errors:IP', 'Errors:URL'
D. create 'WebLogs', 'Errors'
Answer C
Question 10
Which feature of HBase ensures predictable disk head seek performance within a RegionServer? A. Data is stored distributed in HDFS
B. Data stored in HBase is sparse
C. Data is stored sorted on row keys
D. Data is stored as an uninterpreted array of bytes
Answer C
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