Datastax Cassandra Administrator Certification Questions and Answer (Pratice Questions and Dumps)

Question-: Dynamic snitch monitor read latencies to avoid reading from hosts that have slowed down?
A. True
B. False

Answer: A

Explanation: Yes, Dynamic snitch can be used to monitor the read latencies to avoid reading from hosts that have slowed down.



Question-: You are bootstrapping a new node to Cassandra cluster. Which of the following parameters can help in defining number of tokens would be handled by this new node?
A. v_token_count
B. num_tokens
C. initial_tokens
D. additional_tokens

Answer: B

Explanation: Such type of questions are less asked in the exam. Because remembering the parameters are difficult. However, there are some common parameters which are used for the configuration on regular basis or discussed frequently. Hence, you should remember those common once. And num_tokens is such parameter.
num_tokens define the amount of virtual nodes (tokens) the joining node will be assigned during bootstrap.
In the Cassandra cluster default token allocation algorithm for the new node will pick num_tokens which would be random and this new node would be responsible for. Load distribution improves with a higher amount of virtual nodes, but it also increases token management overhead. The default of 256 virtual nodes should provide a reasonable load balance with acceptable overhead.


Question-: If you are restoring a node and want to have the previous tokens it was handling should remain same after restore. Then what is the option from below you would choose?
A. v_token_count
B. num_tokens
C. initial_tokens
D. additional_tokens

Answer: C

Explanation: We can assign the comma separated list of tokens manually with the initial_token values in Cassandra.yaml file. And in this case Cassandra will not do token assignment and skip the token allocation process. This may be useful when doing token assignment with an external tool or when restoring node with its previous tokens.

Related Questions

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Question-: Which of the following statement/s is/are correct for Cassandra?
A. Cassandra support linear performance when scaling nodes in a cluster.
B. You can tune the consistency in Cassandra DB
C. Every row in a table can have different number of columns.
D. Across the Data center it has single point of failure.


Question-: Which of the following statements are correct for querying data from a Cassandra table?
A. In where clause you first provide the partition key and then you can have clustering columns.
B. You cannot perform equality or range queries on clustering columns.
C. All equality comparisons must come before inequality comparisons.
D. Range searches are binary search.


Question-: Which of the following statements are correct for the storage layer of the Apache Cassandra node?
A. Cassandra node must have locally attached storage.
B. Cassandra node can work with Direct Attached Storage.
C. Cassandra best work the SAN (Storage Area Network)
D. Cassandra can work with the SSD
E. Cassandra works well with the Network attached storage.


Question-: Which of the following statements are correct for the underlying storage engine of Cassandra?
A. Cassandra follows read-before-write strategy
B. In most of the cases Cassandra storage engine groups inserts and updates in memory and at intervals write the data to disk in append mode.
C. Cassandra database sequentially writes immutable files.
D. A,B
E. B,C


Question-: Please arrange below in correct order of writing the data by Cassandra Storage engine?

A. Logging data in the commit log
B. Writing data to memtable
C. Flushing data from the memtable
D. Strong data on disk in SSTables


Question-: There are two tables Table_A and Table_B with the following throughput.
- Table_A has extremely high throughput
- Table_B has very low throughput
Which of the following statements are correct with regards to memtable and commit log segments?

A. Commit logs are divided into segments.
B. New writes would happen in new segments only when previous segment is filled.
C. When the commit log reaches its threshold it will forces Table_B memtable to be flushed as well.
D. A,B
E. A,B,C