Every node in a Hadoop cluster will have one or multiple processes running, which would need RAM. The machine itself, which has a Linux file system, would have its own processes that need a specific amount of RAM usage. Therefore, if you have 10 DataNodes, you need to allocate at least 20 to 30 percent towards the overheads, Cloudera-based services, etc. You could have 11 or 12 GB and six or seven cores available on every machine for processing. Multiply that by 10, and that's your processing capacity.
