This document provides an overview and comparison of Apache Hadoop and Apache Spark for big data analytics. It discusses the architectures and functionality of Hadoop MapReduce and HDFS, as well as Spark's RDDs, transformations, and actions. The document demonstrates K-means clustering in both Spark and Hadoop MapReduce and shows that Spark outperforms Hadoop MapReduce, especially for iterative algorithms. While Hadoop remains useful for its features, the combination of Spark and HDFS can achieve high performance for both batch and interactive analytics.