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From "Eli Collins (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HADOOP-7335) Force entropy to come from non-true random for tests
Date Mon, 06 Jun 2011 01:09:47 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-7335?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13044668#comment-13044668
] 

Eli Collins commented on HADOOP-7335:
-------------------------------------

+1  lgtm

OSX has supported /dev/urandom since at least 10.2. From http://developer.apple.com/library/mac/#documentation/darwin/reference/manpages/man4/random.4.html

{quote}
 /dev/urandom is a compatibility nod to Linux. On Linux, /dev/urandom will produce lower quality
output if the entropy pool drains, while /dev/random will prefer to block and wait for additional
entropy to be collected.  With Yarrow, this choice and distinction is not necessary, and the
two devices behave identically. You may use either.
{quote}


> Force entropy to come from non-true random for tests
> ----------------------------------------------------
>
>                 Key: HADOOP-7335
>                 URL: https://issues.apache.org/jira/browse/HADOOP-7335
>             Project: Hadoop Common
>          Issue Type: Improvement
>          Components: build, test
>    Affects Versions: 0.22.0
>            Reporter: Todd Lipcon
>            Assignee: Todd Lipcon
>            Priority: Minor
>         Attachments: hadoop-7335.txt
>
>
> Passing the system property {{-Djava.security.egd=file:///dev/urandom}} forces the JVM
to seed its PRNG from non-true random (/dev/urandom) instead of the true random (/dev/random).
This makes the tests run faster, since without it they often hang waiting for entropy while
Jetty is initializing.
> We should turn this on for the test targets by default, so developers/hudson boxes don't
have to make this change system-wide or use workarounds like rngtools.

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