The Hadoop Distributed File System (HDFS) uses a block replication mechanism to ensure data reliability and availability across the cluster. Each file in HDFS is split into one or more blocks, and these blocks are stored on different DataNodes in the Hadoop cluster.
The replication factor is a configuration setting that determines the number of copies (replicas) of each block to be stored across different DataNodes. The default replication factor in HDFS is three, meaning that for every block of data, three copies are made and stored on three separate DataNodes.
Administrators can change the default replication factor according to the importance of the data and the storage capacity of the cluster. the replication factor in HDFS is a crucial parameter that impacts data reliability, availability, and storage efficiency in a Hadoop cluster.