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

Question-: Which of the following is you should define when setting up multiple datacenter cluster?
A. Use the NetworkTopologyStrategy
B. Use the SimpleStrategy
C. You should use the LOCAL_ONE or LOCAL_QUORUM consistency level to avoid latency during write operation.
D. You should use the EACH consistency level to avoid latency during write operation.
E. You should specify the Snitch.


Answer: A, C, E

Explanation: While using the multiple datacenter setup you should keep following things in the mind at least so that your set up works as expected.

1. Use the NetworkTopologyStrategy.
2. You must consider using consistency level which is either LOCAL_ONE or LOCAL_QUORUM.
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Question-: You have Cassandra cluster setup using one datacenter having total nodes in it. You created keyspace using the following command.
ALTER KEYSPACE HE_KEPSPACE WITH replication={‘class’ : ‘NetworkTopologyStrategy’ , ‘DC1’ : 1 , ‘DC2’ : 2}

Which of the following statement is true?

A. This command would fail because there is only one datacenter and you have defined the two datacenters in the command.
B. This command would be successful and local datacenter would be created using the 3rd node in the cluster.
C. This command would fail as this would not be able to create 3 copy of the data.
D. This command would be successful, without any error.

Answer: D
Exp: Yes, this command would successful even you don’t have two datacenter. This is one of the good strategies to preplan your Keyspace setup. In future, you would like to add new Datacenter in the cluster and that time Keyspace would be replicated on another datacenter.



Question-: If you are adding a new datacenter to your existing cluster then which of the following command you should use?
A. nodetool repair
B. nodetool rebuild
C. nodetool update
D. nodetool refresh

Answer: B
Exp: When you are adding a new datacenter to your existing Cassandra cluster then you should use the “nodetool rebuild� command. This command would operate on the multiple nodes in the cluster and stream the data only from single source replica when rebuilding a token range. This command should be used when you are adding a new datacenter to an existing cluster.

Related Questions

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Question-: You have decided to upgrade your Cassandra cluster from older version to newer version. And also, your older cluster has nodes and now in the new cluster you would be having nodes. Which all things you should do while migration preparation?
A. Configure the same schema in the new 10 node cluster.
B. Configure that client writes should go in both the cluster.
C. Take the snapshot from the old cluster and copy the data files.
D. Take the snapshot from the old cluster and copy the data using sstableloader.
E. Switch to the new cluster


Question-: You are having a node Cassandra cluster with the single token architecture, now you plan to add two more nodes to the Cassandra cluster. Which of the following is true in this case?
A. Existing node should keep their existing token assignments.
B. New nodes are assigned tokens that bisect the existing token range.
C. You have to re-calculate the tokens for the entire cluster, and assign the new tokens to the existing nodes.
D. It is fine, if you are having old data on the new nodes.


Question-: You are adding new node to the existing Cassandra cluster which has single token architecture. You must keep the initial_token property as blank?
A. True
B. False


Question-: You are planning to setup new Cassandra cluster with the single token architecture and should span datacenters. It is ideal to have seed nodes from the single datacenter only?
A. True
B. False


Question-: ___________________ refers to how up-to-date and synchronized a row of data is on all of its replicas.
A. Transaction
B. Compaction
C. Consistency
D. Compression


Question-: Which of the following command would flush the memtable without listening for connections to other nodes?
A. nodetool drain
B. nodetool flush
C. nodetool commit
D. nodetool tpstats