Cloudera Cloudera Certifications CCB-400 Questions & Answers

• Question 41:

  Under default settings, which feature of HBase ensures that data won't be lost in the event of a RegionServer failure?

  A. AllHBase activity is written to the WAL, which is stored in HDFS

  B. All operations are logged on theHMaster.

  C. HBase is ACID compliant, which guarantees that itis Durable.

  D. Data is stored on the local filesystem of the RegionServer.

  Correct Answer: A

  Reference:http://tm.durusau.net/?p=27674(See `From the post' second paragraph)

• Question 42:

  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'}

  Correct Answer: D

• Question 43:

  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.

  Correct Answer: C

  Reference:http://archive.cloudera.com/cdh4/cdh/4/hbase/book.html#delete(scroll below and see 5.8.1.5. Delete topic, read the last paragraph)

• Question 44:

  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

  Correct Answer: D

• Question 45:

  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 queryZooKeepertofind the location of the new HMaster and complete the metadata change.

  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. Theclientapplication will fail with a runtime error.

  Correct Answer: A