Three types of sinks in Flume
Collector Tier Event
This is where you would land a flow (or possibly multiple flows joined together) into an HDFS-formatted file system.
Agent Tier Event
This is used when you want the sink to be the input source for another operation. When you use these sinks, Flume will also ensure the integrity of the flow by sending back acknowledgments that data has actually arrived at the sink.
This sink can be a text file, the console display, a simple HDFS path, or a null bucket where the data is simply deleted.