# Buffer

The [`buffer`](https://docs.fluentbit.io/manual/3.2/concepts/buffering) phase in the pipeline aims to provide a unified and persistent mechanism to store your data, using the primary in-memory model or the file system-based mode.

The `buffer` phase contains the data in an immutable state, meaning that no other filter can be applied.

{% @mermaid/diagram content="graph LR
accTitle: Fluent Bit data pipeline
accDescr: A diagram of the Fluent Bit data pipeline, which includes input, a parser, a filter, a buffer, routing, and various outputs.
A\[Input] --> B\[Parser]
B --> C\[Filter]
C --> D\[Buffer]
D --> E((Routing))
E --> F\[Output 1]
E --> G\[Output 2]
E --> H\[Output 3]
style D stroke:darkred,stroke-width:2px;" %}

Buffered data uses the Fluent Bit internal binary representation, which isn't raw text.

Fluent Bit offers a buffering mechanism in the file system that acts as a backup system to avoid data loss in case of system failures.