4、NameNode啟動過程詳解
阿新 • • 發佈:2019-01-03
NameNode
- 記憶體
- 本地磁碟
- fsimage
- edits
第一次啟動HDFS
- 格式化HDFS,目的就是生成fsimage
- start NameNode,讀取fsimage檔案
- start DataNode,向NameNode註冊;block report(塊彙報)
- create dir /user/hw/tmp -> write [edits]
- put files /user/beifeg/tmp(*-site.xml) -> write [edits]
- delete file /user/beifeng/tmp/core-site.xml -> write [edits]
第二次啟動HDFS
- NameNode
- read [fsimage]
- read [edits]
- gen write fsimage [new]
- gen edits [null]
- DataNode
- 註冊
- block report
- create dir /user/beifeng/tmp -> write [edits]
- put files /user/beifeg/tmp(*-site.xml) -> write [edits]
- delete file /user/beifeng/tmp/core-site.xml -> write [edits]
SecondaryNameNode輔助功能講解
- NameNode中的編輯日誌檔案太大的話如何處理。需要藉助SecondaryNameNode.
- 定期的合併 fsimage+edits ->new fsimage