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  1. Hadoop HDFS
  2. HDFS-3290

Use a better local directory layout for the datanode

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    Details

    • Type: Improvement
    • Status: Resolved
    • Priority: Minor
    • Resolution: Duplicate
    • Affects Version/s: 0.23.0
    • Fix Version/s: None
    • Component/s: None
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      Description

      When the HDFS DataNode stores chunks in a local directory, it currently puts all of the chunk files into either one big directory, or a collection of directories. However, there is no way to know which directory a given block will end up in, given its ID. As the number of files increases, this does not scale well.

      Similar to the git version control system, HDFS should create a few different top level directories keyed off of a few bits in the chunk ID. Git uses 8 bits. This substantially cuts down on the number of chunk files in the same directory and gives increased performance, while not compromising O(1) lookup of chunks.

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              • Assignee:
                cmccabe Colin McCabe
                Reporter:
                cmccabe Colin McCabe
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                • Created:
                  Updated:
                  Resolved: