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

Question-: In your organization network team is changing the topology, hence they have to change the IP address for one of the nodes in Cassandra cluster. This setup is not using the PropertyFileSnitch as “endpoint_snitch�. What all steps you need to follow for that?
A. Run the “nodetool drain� command
B. Update the Cassandra.yaml file with the new IP details
C. Stop and then start the Cassandra on this node
D. Initiate the rolling start of the Cassandra cluster

Answer: A,B,C

Explanation: When you have to change the IP address of an existing node in the Cassandra cluster you need to follow the below steps in order.
1. Run the “nodetool drain� command, which flushes all the memtables to the SSTable on the disk.
2. Now stop the Cassandra on this node.
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4. If the node is a seed node, then we have to update the -seeds parameter in the seed_provided list “Cassandra.yaml� file on all the nodes.
5. If the endpoint_snitch is PropertyFileSnitch, add an entry for the new IP address in the Cassandra-topology.properties file on all nodes. Also make sure that you would not remove the entry for the old IP address.
6. We need to update the DNS and the local host.
7. Start the Cassandra on this node.
8. If you are using the “PropertyFileSnitch� then perform a rolling restart.



Question-: You have just setup the cluster and not made it operational yet. Now you found that, you need to switch the snitch for a particular node. For switching the snitch you always have to setup the Cassandra cluster from scratch?
A. True
B. False

Answer: B

Explanation: If data is not inserted in the Cassandra cluster yet, so there is no change in the topology of the Cassandra cluster. This means that you only need to set the snitch and no other steps are needed.



Question-: You have an node Cassandra cluster, currently setup in the single datacenter. You need to move nodes from the cluster in new datacenter, which would be part of the same cluster having nodes in each datacenter. Which of the following you would be doing at the minimum?
A. Alter the keyspace replication settings to reflect the two datacenters.
B. Once data is replicated to the new datacenter, remove the number of nodes from the original datacenter that have moved to new datacenter.
C. Decommission 4 nodes from the cluster
D. Use the “nodetool assassinate� command on the 4 nodes which you would be moving

Answer: 1, 2
Answer: This question is talking about moving node from one datacenter to another datacenter. Technically splitting the datacenters. What you can do first create a new datacenter with the nodes you want to move. Then alter the keyspace replication settings for the keyspace originally existed to reflect that two datacenters exist. Once data is replicated to the new datacenter, remove the number of nodes from the original datacenter that have “moved� to the new datacenter.

Related Questions

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Question-: There are various types of partitioner provided for the Cassandra storage engine. What exactly this partitioner does?
A. It takes the partition key and then generate the partition token for that key.
B. It takes the clustering column values and then generate the partition token for that key.
C. It helps in updating the partition Key index regularly.
D. It helps in removing tombstone record from the SSTable


Question-: Which of the following is/are correct?
A. Partition Key = Primary Key
B. Primary Key = Partition Key + Clustering Column
C. Clustering Column = Partition Key + Primary Key
D. Partition Key = Clustering Column + Primary Key


Question-: Either of the clustering or partition key columns are required?
A. True
B. False


Question-: when you use the clustering columns
A. While writing the data, memtable also sort the data based on clustering column.
B. While writing the data, commit log also sort the data based on clustering column.
C. Based on the clustering column new commit log files are created.
D. While reading the data, engine would always get the data sorted by clustering column.



Question-: Select correct statement with regards to Chunk cache and OS cache.
A. OS page cache is sized dynamically by the OS.
B. Chunk cache is sized dynamically by the OS.
C. OS page cache size should be predefined and remain static.
D. Chunk cache size should be predefined and remain static.
E. You should always keep the chunk cache very high.



Question-: Which of the following is true for the Cassandra clocks?
A. Cassandra uses the Network Time Protocol to synchronize the clocks on all nodes and application servers.
B. Cassandra always uses the local time stamp of the node for storing timestamp with the data.
C. Cassandra always uses the UTC time stamp of the node for storing timestamp with the data.
D. Cassandra recommend that you install the either Google or Redhat clock service on the Node.