For cost-efficient, low-risk environments, what HDFS replication factor is recommended?

In cost-efficient, low-risk environments, a replication factor of 2 for HDFS (Hadoop Distributed File System) is recommended because it strikes a balance between ensuring data availability and maintaining resource efficiency.

When data is replicated, having at least two copies allows for fault tolerance; if one node fails, the data can still be accessed from the second node. This setup effectively provides redundancy without significantly increasing storage costs, as each file only takes up about twice the space of its original size.

A replication factor of 2 is particularly suitable for environments where minimizing costs is essential and the risk associated with data loss is manageable. It ensures that while data redundancy is achieved, the overhead in terms of disk space and network bandwidth is not excessive, which can be critical in cost-sensitive scenarios.

In higher replication factors, such as 3 or 4, while data durability increases further, they also lead to increased storage consumption and potentially higher costs, which may not be justified in lower-risk situations. Therefore, a replication factor of 2 is optimal for balancing the need for reliability with budgetary constraints.