[jira] [Created] (HDFS-9789) Correctly update DataNode's scheduled block size when writing small EC file

["Jing Zhao (JIRA)" <ji...@apache.org>]

Jing Zhao created HDFS-9789:
-------------------------------

             Summary: Correctly update DataNode's scheduled block size when writing small EC file
                 Key: HDFS-9789
                 URL: https://issues.apache.org/jira/browse/HDFS-9789
             Project: Hadoop HDFS
          Issue Type: Sub-task
          Components: namenode
    Affects Versions: 3.0.0
            Reporter: Jing Zhao
            Assignee: Jing Zhao


Currently DatanodeDescriptor's scheduled block size is increased when allocating a new block. It is then decreased when NN receives IBR from the DN.

When writing an erasure-coded file whose size is less a stripe, we can have less than 6 internal data blocks. Then we never decrease the scheduled block size for Datanodes that are actually not used for storing any internal block. When writing large amount of small EC files within a short period, this may cause NN to wrongly exclude DN for writing due to high scheduled block size.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)