Over a period of time, the Hadoop clusters grow in size and the hardware will change. More powerful nodes, with faster CPU, disks, and RAM, will be added and there will be an uneven performance of nodes across the cluster.
This can be controlled at the node level using YARN labels, which we will see at a later stage in the book. We can also configure storage-based policies according to the disk drives we have such as SSDs, SATA, and PATA.
For this recipe, you will again need a running cluster with at least HDFS configured and Datanodes in the cluster with different types of hard drives. Some nodes have slow disk drives and others have fast disk drives.
The segregation can also be based on the cost factor, ...