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  1. Hadoop HDFS
  2. HDFS-14657

Refine NameSystem lock usage during processing FBR

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    Details

    • Type: Improvement
    • Status: Patch Available
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: None
    • Labels:
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      Description

      The disk with 12TB capacity is very normal today, which means the FBR size is much larger than before, Namenode holds the NameSystemLock during processing block report for each storage, which might take quite a long time.

      On our production environment, processing large FBR usually cause a longer RPC queue time, which impacts client latency, so we did some simple work on refining the lock usage, which improved the p99 latency significantly.

      In our solution, BlockManager release the NameSystem write lock and request it again for every 5000 blocks(by default) during processing FBR, with the fair lock, all the RPC request can be processed before BlockManager re-acquire the write lock.

        Attachments

        1. HDFS-14657.002.patch
          12 kB
          Chen Zhang
        2. HDFS-14657-001.patch
          9 kB
          Chen Zhang

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              • Assignee:
                zhangchen Chen Zhang
                Reporter:
                zhangchen Chen Zhang
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                • Created:
                  Updated: