File channel

A file channel is a channel that stores events to the local filesystem of the agent. While slower than the memory channel, it provides a durable storage path that can survive most issues, and should be used in use cases where a gap in your data flow is undesirable.

This durability is provided by a combination of a Write Ahead Log (WAL) and one or more file storage directories. The WAL is used to track all input and output from the channel in an atomically safe way. In this way, if the agent is restarted, the WAL can be replayed to make sure all the events that came into the channel (puts) have been written out (takes) before the storage of the data can be purged from the local filesystem.

Additionally, the file channel supports encrypting data written to the filesystem should your data handling policy require that all data on disk (even temporarily) be encrypted. I won't cover this here, but if you need it, there is an example in the Flume User Guide (http://flume.apache.org/FlumeUserGuide...