How do you maintain high availability during data replication in Cassandra?

Maintaining high availability during data replication in Cassandra is primarily achieved by implementing appropriate replication strategies. Cassandra offers various replication strategies that determine how data is replicated across the cluster to ensure that it is always available, even in the event of node failures.

Choosing a replication strategy such as SimpleStrategy or NetworkTopologyStrategy allows you to control how many copies of the data are created and where they are stored. For example, in a multi-data center setup, NetworkTopologyStrategy can be used to replicate data across various data centers, ensuring that even if one data center goes down, the data is still accessible from another location.

This approach increases resilience and allows for continuity of service because it produces multiple copies of the data across different nodes. If one or more nodes become unavailable, requests can still be successfully serviced by other nodes that hold replicas. Therefore, utilizing robust replication strategies is essential for achieving high availability in Cassandra, as it directly impacts the system's ability to withstand failures without compromising data access.