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



Question-: While adding a new node to the cluster. New node must know the IP addresses of the seed nodes?
A. True
B. False

Answer: A
Exp: Yes, if you are adding a new node to the cluster. It should know that to which node, it is going to contact in the cluster. To get all the required detail for the cluster before joining. These are the IP addresses of the seed nodes, which can be set in the Cassandra.yaml file of the bootstrapping node.



Question-: Which of the following is recommended way to removing a node from the Cassandra cluster?
A. nodetool decommission
B. nodetool removenode
C. nodetool assassinate
D. nodetool cleanup

Answer: A
Exp: When you want to remove a node from the Cassandra cluster than you should always prefer the decommission command, its lengthy command. But does things appropriately.
When you want to decrease the cluster size and node is in active state then you should go with the “nodetool decommission� command. With the decommission command data would be transferred from the decommissioned node to other active nodes in the cluster. If you have a cluster with the v-nodes enabled then cluster rebalancing happens automatically.
If cluster architecture is based on the Single token architecture then you need to manually rebalance the cluster. And arrange the token ranges from the decommissioned nodes to the remaining nodes.



Question-: When you use the decommission command to remove a node from the Cassandra cluster. It would shut down the node immediately?
A. True
B. False

Answer: B

Explanation: No, when you use the decommission command it would not shutdown the node immediately. It would be shutdown only when decommissioning completes. You can use the “nodetool netstats� command to check the overall progress.

Related Questions


Question-: In your Cassandra cluster you have nodes, and you want to keep replication factor as . And you will be adding one additional node to the cluster after a month. In this case keeping replication factor is fine?
A. Yes
B. No


Question-: Which of the following best replication strategy for production Cassandra Cluster setup. Assuming you have Cassandra cluster with nodes, which are across datacenters in Europe, North America and Asia region?

A. SimpleNetworkStrategy
B. SimpleStrategy
C. DatacenterAwareTopology
D. DatacenterAwareNetworkTopology
E. NetworkTopologyStrategy


Question-: Please match the below

A. Virtual Nodes
B. Single Token Architecture
C. Murmur3Partitioner
D. RandomPartitioner
E. Snitch

1. The possible range of hash value is from 0 to 2^127 -1
2. Range of partition key token between -2^63 tp +2^63-1
3. It uses either allocation algorithm or random selection algorithm to specify the number of tokens.
4. You must have to enter the values in the initial_token parameter in the Cassandra.yaml file.
5. It can be used to find which datacenters and racks nodes below to.


Question-: Hinted handoff is repair mechanism when
A. Read fails on a node
B. Write fails on a node
C. Both read and write fails on a node
D. In case of new node is added to cluster. It will be SyncUP using Hinted Handoff


Question-: You have a Cassandra cluster with the two nodes (X and Y) with replication factor is and consistency level is also one. You are writing one row named row key K. Here node X is coordinator node before writing the data node-x goes down, which of the following statement is correct?
A. Node X will not be able to store hint.
B. Node Y has not received data as coordinator node, hence it can not write.
C. Coordinator node will return an UnavailableException error.
D. None of the above


Question-: Read repair does not propagate expired tombstones, nor does it consider expired tombstones when actually repairing data. And during read repair if there is tombstone data that has not been propagated to all replica nodes before gc grace expired, this data may continue to be returned as live data?
A. True
B. False