[jira] [Updated] (ACCUMULO-3957) Consider moving off getContentSummary in the monitor

["Josh Elser (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ACCUMULO-3957?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Josh Elser updated ACCUMULO-3957:
---------------------------------
    Fix Version/s:     (was: 1.5.4)
                       (was: 1.6.4)
                       (was: 1.7.1)

> Consider moving off getContentSummary in the monitor
> ----------------------------------------------------
>
>                 Key: ACCUMULO-3957
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-3957
>             Project: Accumulo
>          Issue Type: Bug
>          Components: monitor
>            Reporter: Josh Elser
>            Assignee: Josh Elser
>            Priority: Critical
>             Fix For: 1.8.0
>
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> Recently heard about an issue where a large Hadoop installation which had Accumulo running was experiencing long pauses in the Namenode. Inspecting NN audit logs, it was found that the user running Accumulo issues a {{getContentSummary("/")}} call just before the NN pauses were experienced.
> In {{DefaultServlet.java}}, we use this call to compute the total HDFS disk usage and present a ratio of space that Accumulo uses relative to the total available space.
> It's still unclear why this was causing issues in this case (as this operation should only be acquiring a read-lock in the namenode), it was recommended to me that Accumulo use the JMX metrics for the NN instead of making this call.



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