December 2012
Intermediate to advanced
572 pages
13h 8m
Chinese
Content preview from HBASE技術手冊
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第八章
複製
HBase 複製是在 HBase 部署環境間，複製資料的一種方式。它可以作為一種災難復原的
解決方案，也在 HBase 上，對於提供高可用性有所貢獻。它還提供更多實務的目的：例
如：可以作為從網站導向的叢集中，拷貝最新的異動內容到 MapReduce 叢集的一種簡
單方式，然後利用 MapReduce 叢集對舊及新的資料進行處理，再自動地送回結果。
HBase 複製採用的基本架構模式是：“（HBase 叢集）master 推送”；因為每個 region 伺
服器都有自己的預先寫入日誌（即 WAL 或
HLog）
，這樣就很容易記錄現在正在複製什
麼，非常類似於其他一些著名的解決方案，就像 MySQL 的主從複製，就只記錄了一個
二進位日誌（binary log）。一個 master 叢集可以複製到任意數量的 slave 叢集，同時每
個 region 伺服器會參與它本身所對應的一系列修改的複製。
複製是採非同步來進行的，這意味著參與的叢集可能在地理位置上是相隔甚遠，它們之
間的連接在某段時間內可能是離線的，插入到 master 叢集中的那些列，在同一時間在
slave 叢集上不一定是可用的（最終會具有一致性）。
圖 8-12 說明複製運作的全貌。
圖 8-12 複製架構的全貌
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.