【基礎架構】不同場景下的數據存儲技術，你用對了嗎？

{"type":"doc","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在企業的IT基礎架構體系中，數據是非常重要的一個部分，而數據又都是存在存儲設備裏面，故存儲設備的選型及相關的技術，便顯得非常重要。"}]},{"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":"本文旨在講述存儲的各方面概念之餘，提出相對各種場景最適合使用的存儲技術，以供實踐參考。"}]},{"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":"提到存儲，首先需要思考一個問題：爲什麼需要存儲？"}]},{"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":"假如有100TB的數據，買來100GB大小的磁盤來存放，則需要1000個。"}]},{"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":"那麼，如何將1000個硬盤連接起來呢？如果用一般的PC，則需要250臺。"}]},{"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":"數據存放起來了，如何管理和使用？性能如何？當設備損壞或發生事故時如何應對？這些都在下文中進行逐一討論。"}]},{"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":"總而言之，存儲主要解決了以下的幾個主要問題："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"容量"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"速度"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"易於管理"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"安全：容災與備份"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"可擴展性"}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"發展歷史"}]},{"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":"提到存儲的發展歷史，不得不提到IT技術的發展趨勢，從大型機到小型機，到X86服務器，再到雲主機，IT技術經歷了一系列的迭代變革。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/17/172d74f414275a1c4f0933d85be6b135.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"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":"跟隨着IT技術的進步，存儲技術也隨之有了發展，存儲產品的發展歷程就是數據保存、應用發展的過程。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/89/89da8ab3be594572ac927f9404d5e4e2.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"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":"存儲產品的趨勢是，使用統一存儲，即通過整合降低成本，將NAS和SAN結合起來，簡化存儲管理，提高利用率。EMC在2010年推出了VNX系列產品，首次推出了統一存儲的概念，HDS在2012年跟進，推出了HUS系列產品。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/3f/3f9cb7c66ef1112c198a22d2bbd380ea.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"企業級存儲分類"}]},{"type":"paragraph","attrs":{"indent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Attached Storage）直接掛接存儲"}]},{"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":"NAS（Network Attached Storage）網絡掛接存儲"}]},{"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":"SAN（Storage Area Network）存儲區域網絡（包括FC SAN、IP SAN）"}]},{"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":"01 DAS"}]},{"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":"開放系統的直接掛接存儲(Direct Attached Storage，簡稱DAS)已經有近四十年的使用歷史，隨着用戶數據的不斷增長，尤其是數百GB以上時，其在備份、恢復、擴展、災備等方面的問題變得日益困擾系統管理員。"}]},{"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":"直連式存儲與服務器主機之間的連接通道通常採用SCSI連接，隨着服務器CPU的處理能力越來越強，存儲硬盤空間越來越大，陣列的硬盤數量越來越多，SCSI通道將會成爲IO瓶頸；服務器主機SCSI ID資源有限，能夠建立的SCSI通道連接有限。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/53/5301a5d43f9f72cd78b92c1a7dd4ec3c.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"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":"02 NAS"}]},{"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":"NAS（Network Attached Storage：網絡掛接存儲）按字面簡單說就是連接在網絡上，具備資料存儲功能的裝置，因此也稱爲“網絡存儲器”。它是一種專用數據存儲服務器。它以數據爲中心，將存儲設備與服務器徹底分離，集中管理數據，從而釋放帶寬、提高性能、降低總擁有成本、保護投資。其成本遠遠低於使用服務器存儲，而效率卻遠遠高於後者。"}]},{"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":"NAS解決方案通常配置爲作爲文件服務的設備，由工作站或服務器通過網絡協議（如TCP/IP）和應用程序（如網絡文件系統NFS或者通用Internet文件系統CIFS）來進行文件訪問。大多數NAS連接在工作站客戶機和NAS文件共享設備之間進行。這些連接依賴於企業的網絡基礎設施來正常運行"}]},{"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":"NAS的優點是支持文件共享，易於管理，缺點是其爲網絡盤，而不是系統本地SCSI盤，不支持本地文件系統，軟件兼容性差（某些數據庫和系統級軟件不可以使用）。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/14/144a1260133a52503db3fd1f266ef433.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"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":"03 SAN"}]},{"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":"存儲區域網絡（Storage Area Network，簡稱SAN）採用網狀通道（Fibre Channel ，簡稱FC，區別與Fiber Channel光纖通道）技術，通過FC交換機連接存儲陣列和服務器主機，建立專用於數據存儲的區域網絡。SAN經過十多年曆史的發展，已經相當成熟，成爲業界的事實標準（但各個廠商的光纖交換技術不完全相同，其服務器和SAN存儲有兼容性的要求）。"}]},{"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":"SAN實際是一種專門爲存儲建立的獨立於TCP/IP網絡之外的專用網絡。目前一般的SAN提供2Gb/S到4Gb/S的傳輸速率，同時SAN網絡獨立於數據網絡存在，因此存取速度很快，另外SAN一般採用高端的RAID陣列，使SAN的性能在幾種專業存儲方案中傲視羣雄。"}]},{"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":"SAN由於其基礎是一個專用網絡，因此擴展性很強，不管是在一個SAN系統中增加一定的存儲空間還是增加幾臺使用存儲空間的服務器都非常方便。通過SAN接口的磁帶機，SAN系統可以方便高效的實現數據的集中備份。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/19/19c59cce819c0b320ccc46fce34b325d.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"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":"目前常見的SAN有FC-SAN和IP-SAN，其中FC-SAN爲通過光纖通道協議轉發SCSI協議，IP-SAN通過TCP協議轉發SCSI協議。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/19/19c59cce819c0b320ccc46fce34b325d.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"存儲技術"}]},{"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":"01 磁盤陣列"}]},{"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":"磁盤陣列又叫RAID（廉價磁盤冗餘陣列），是指將多個類型、容量、接口，甚至品牌一致的專用硬磁盤或普通硬磁盤連成一個陣列，使其能以某種快速、準確和安全的方式來讀寫數據，從而達到提高數據讀取速度和安全性的一種手段。"}]},{"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":"因此，磁盤陣列讀寫方式的基本要求是，在儘可能提高磁盤數據讀寫速度的前提下，必須確保在一張或者多張磁盤失效時，陣列能夠有效地防止數據丟失。"}]},{"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":"磁盤陣列的最大特點是數據存取速度特別快，其主要功能是可提高網絡數據的可用性及存儲容量，並將數據有選擇性地分佈在多個磁盤上，從而提高系統的數據吞吐率。"}]},{"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":"以下是磁盤陣列的一些概念："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"bulletedlist","content":[{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"磁盤陣列："},{"type":"text","text":"指存儲設備所有的元件(包含控制器硬盤、電源、扇等等)。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"控制器："},{"type":"text","text":"可理解是用來管理存儲中的硬盤,用來管理數據存儲裝置。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"磁盤："},{"type":"text","text":"控制器是用來讀寫數據,則磁盤是用來存儲數據的。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"擴展櫃："},{"type":"text","text":"指的是放硬盤的盒子,如果把控制器的角色比喻成火車頭,那這個就是車廂。"}]}]},{"type":"listitem","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"控制器電池："},{"type":"text","text":"是用於保護控制器緩存的數據 ,數據存入硬盤時,要先通過控制器進行算法運算後再存入硬盤,而這個操作會存在一定延時,如果此時掉電,這一時間段的數據就會丟失,使用電池後,在一定的時間內可以保障數據不丟失。電池還有另- -個用途就是可以提升控制器性能。默認讀緩存(cache)是開啓的,但寫緩存是沒啓用的,因此電池在這裏就用作寫緩存使用。"}]}]}]},{"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":"備註：磁盤陣列這裏的控制器,對應PC服務器上的RAID陣列卡。"}]},{"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":"RAID產生的原因可以歸納如下："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/60/60e4f8bee85ce3e0e07cae117f1942c0.png","alt":null,"title":null,"style":null,"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"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":"RAID由幾個硬盤組成，從整體上看相當於一個物理卷，在物理卷的基礎上可以按照指定容量創建一個或多個邏輯卷，通過LUN（Logic Unit Number）來標識。"}]},{"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":"磁盤陣列有以下幾種工作模式："}]},{"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":"RAID0, RAID1, RAID3, RAID5, RAID6, RAID10"}]},{"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":"此處我們僅討論RAID0, RAID1, RAID5, 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Drives)，簡稱固盤。"}]},{"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":"固態硬盤(Solid State 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NFS"}]},{"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":"網絡文件系統是FreeBSD支持的文件系統中的一種,也被稱爲NFS(Network File System)。NFS允許一個系統在網絡上與他人共享目錄和文件。通過使用NFS，用戶和程序可以像·訪問本地文件一樣訪問遠端系統上的文件。"}]},{"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":"NFS至少有兩個主要部分:一臺服務器和一臺(或者更多)客戶機。客戶機遠程訪問存放在服務器上的數據。爲了正常工作, 一些進程需要被配置並運行。"}]},{"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":"注: NFS由Sun microsystems公司開發。是一種網絡文件系統，並且是unix/linux操作系統的協議。"}]},{"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":"09 CIFS"}]},{"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":"CIFS（Common Internet File System）使程序可以訪問遠程Internet計算機上的文件並要求此計算機的服務。CIFS 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