分佈式文件系統架構對比

{"type":"doc","content":[{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"什麼是文件系統？"}]},{"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":"文件系統是計算機中一個非常重要的組件，爲存儲設備提供一致的訪問和管理方式。在不同的操作系統中，文件系統會有一些差別，但也有一些共性幾十年都沒怎麼變化：數據是以文件的形式存在，提供 Open、Read、Write、Seek、Close 等API 進行訪問；"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"文件以樹形目錄進行組織，提供原子的重命名（Rename）操作改變文件或者目錄的位置。"}]}]}]},{"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":"文件系統提供的訪問和管理方法支撐了絕大部分的計算機應用，Unix 的“萬物皆文件”的理念更是凸顯了它的重要地位。"}]},{"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":"文件系統的複雜性使得它的可擴展性未能跟得上互聯網的高速發展，極大簡化了的對象存儲及時填補了空缺得以快速發展起來。因爲對象存儲缺乏樹狀結構也不支持原子重命名操作，跟文件系統有很大的差別，本文暫不討論。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"單機文件系統的挑戰"}]},{"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":"絕大多數文件系統都是單機的，在單機操作系統內爲一個或者多個存儲設備提供訪問和管理。隨着互聯網的高速發展，單機文件系統面臨很多的挑戰："}]},{"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：無法同時爲分佈在多個機器中的應用提供訪問，於是有了 NFS 協議，可以將單機文件系統通過網絡的方式同時提供給多個機器訪問。"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"容量：無法提供足夠空間來存儲數據，數據只好分散在多個隔離的單機文件系統裏。"}]}]}]}]}