[jira] [Created] (HDFS-4804) WARN when users set the block balanced preference percent below 0.5 or above 1.0

["Stephen Chu (JIRA)" <ji...@apache.org>]

Stephen Chu created HDFS-4804:
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             Summary: WARN when users set the block balanced preference percent below 0.5 or above 1.0
                 Key: HDFS-4804
                 URL: https://issues.apache.org/jira/browse/HDFS-4804
             Project: Hadoop HDFS
          Issue Type: Improvement
    Affects Versions: 2.0.4-alpha
            Reporter: Stephen Chu
            Assignee: Stephen Chu
            Priority: Minor


With the new feature added in HDFS-1804 (Add a new block-volume device choosing policy that looks at free space), it'd be useful to have a WARN log if the operator  sets dfs.datanode.fsdataset.volume.choosing.balanced-space-preference-percent to a value greater than 1.0. This might happen if the operator mistakenly assumes that this setting takes in a percentage number from 0.0-100.0, while the setting actually takes a range 0.0-1.0.

Also, it'd be useful to WARN in the case that value is set below 0.5, which would cause disks with less free space to get more block allocations.

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