Question-6: Which of the following is/are correct for the Datacenter?
- Datacenter can be physical or virtual.
- Data cannot be replicated across the data center.
- Datacenters must be across physical locations
- A Datacenter must have at least two cluster in it.
Ans : A
Exp: Let’s first understand few terminologies with regards to Cassandra database setup
Node: This is very basic using where your data will be stored. You can assume it as a one computer/laptop/server.
Cluster: Group of nodes which are distributed and connected, a cluster can have one or more nodes. Even a cluster can have single Datacenter or multiple Datacenter.
Datacenter: As we discussed cluster can have related nodes together for replication purposes. You can have either physical or virtual datacenter. Using separate datacenters prevents transactions from being impacted by other workloads and lower latency. Based on replication factor setting data can be written to multiple datacenters. Datacenter must never span physical locations.
A cluster can have multiple Datacenter in it, but Datacenter may not have multiple cluster in it. It is possible more than one Cassandra setup can exist in a single datacenter.
