分布式文件系统架构对比

{"type":"doc","content":[{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"什么是文件系统？"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"bulletedlist","content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"文件系统是计算机中一个非常重要的组件，为存储设备提供一致的访问和管理方式。在不同的操作系统中，文件系统会有一些差别，但也有一些共性几十年都没怎么变化：数据是以文件的形式存在，提供 Open、Read、Write、Seek、Close 等API 进行访问；"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"文件以树形目录进行组织，提供原子的重命名（Rename）操作改变文件或者目录的位置。"}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"文件系统提供的访问和管理方法支撑了绝大部分的计算机应用，Unix 的“万物皆文件”的理念更是凸显了它的重要地位。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"文件系统的复杂性使得它的可扩展性未能跟得上互联网的高速发展，极大简化了的对象存储及时填补了空缺得以快速发展起来。因为对象存储缺乏树状结构也不支持原子重命名操作，跟文件系统有很大的差别，本文暂不讨论。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"单机文件系统的挑战"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"绝大多数文件系统都是单机的，在单机操作系统内为一个或者多个存储设备提供访问和管理。随着互联网的高速发展，单机文件系统面临很多的挑战："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"bulletedlist","content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"共享：无法同时为分布在多个机器中的应用提供访问，于是有了 NFS 协议，可以将单机文件系统通过网络的方式同时提供给多个机器访问。"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"容量：无法提供足够空间来存储数据，数据只好分散在多个隔离的单机文件系统里。"}]}]}]}]}