Final answer:
A DataNode is a component of Hadoop that stores actual data in HDFS. Multiple instances of DataNodes run on a Hadoop Cluster.
Step-by-step explanation:
A DataNode is a component of the Hadoop Distributed File System (HDFS) that stores actual data in Hadoop. It is responsible for reading and writing data to the file system.
In a Hadoop Cluster, multiple instances of DataNodes run on different machines. The number of instances can vary depending on the size of the cluster and the configuration settings. It is common to have several DataNodes in a cluster to distribute the storage and processing of data.