不多说，直接上干货！
一切来源于官网
http://kafka.apache.org/documentation/
Kafka as a Storage System
kafka作为一个存储系统
Any message queue that allows publishing messages decoupled from consuming them is effectively acting as a storage system for the in-flight messages. What is different about Kafka is that it is a very good storage system.
所有发布消息到消息队列和消费分离的系统，实际上都充当了一个存储系统（发布的消息先存储起来）。Kafka比别的系统的优势是它是一个非常高性能的存储系统。
Data written to Kafka is written to disk and replicated for fault-tolerance. Kafka allows producers to wait on acknowledgement so that a write isn't considered complete until it is fully replicated and guaranteed to persist even if the server written to fails.
写入到kafka的数据将写到磁盘并复制到集群中保证容错性。并允许生产者等待消息应答，直到消息完全写入。
The disk structures Kafka uses scale well—Kafka will perform the same whether you have 50 KB or 50 TB of persistent data on the server.
kafka的磁盘结构 - 无论你服务器上有50KB或50TB，执行是相同的。
As a result of taking storage seriously and allowing the clients to control their read position, you can think of Kafka as a kind of special purpose distributed filesystem dedicated to high-performance, low-latency commit log storage, replication, and propagation.
client来控制读取数据的位置。你还可以认为kafka是一种专用于高性能，低延迟，提交日志存储，复制，和传播特殊用途的分布式文件系统。