Cassandra Partitioning, High Availability, and Consistency - Real-time Analytics with Storm and Cassandra - page 160

Quiz time
Q.1. State whether the following statements are true or false:
1. Cassandra has a default consistency of ALL .
2. QUORUM is the consistency level that provides the highest availability.
3. Cassandra uses a snitch to identify the closeness of the nodes.
4. Cassandra reads and writes features have consistency level 1 by default.
Q.2. Fill in the blanks:
1. _______________ is used to determine the physical closeness of the nodes.
2. _______________ is the consistency that provides the highest availability and low-
est availability.
3. The ___________ is the service that ensures that a node, which has been down for
a while, is correctly updated with the latest changes.
Q.3. Execute the following use case to see Cassandra high availability and replications:
1. Create a four-node Cassandra cluster.
2. Create a keyspace with a replication factor of 3.
3. Add some data into a column family under this keyspace.
4. Attempt to retrieve data using read consistency with using ALL in select query.
5. Shut down the Cassandra daemon on one node and repeat step 4 from the other
three live nodes.
6. Shut down the Cassandra daemon on one node and repeat step 4 from the other
three live nodes using the consistency ANY .
7. Shut down two nodes and update an existing value using a write consistency of
ANY .
8. Attempt a read using ANY .
9. Bring back the nodes that are down and execute read using the consistency ALL
from all four nodes.