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https://issues.apache.org/jira/browse/HADOOP-7832?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13152350#comment-13152350
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Todd Lipcon commented on HADOOP-7832:
-------------------------------------
nice analysis - makes sense. Another big benefit that I'm hoping to see from
the fadvise stuff is preventing flush-out of dentries and inodes. On clusters
with lots of blocks, we see block reports taking many minutes to generate (and
incurring lots of seeks) because the FS metadata gets evicted when MR jobs run.
> Using mincore to understand the effect of fadvise in the Linux page cache
> -------------------------------------------------------------------------
>
> Key: HADOOP-7832
> URL: https://issues.apache.org/jira/browse/HADOOP-7832
> Project: Hadoop Common
> Issue Type: Sub-task
> Components: io, native, performance
> Reporter: Cristina L. Abad
> Priority: Minor
> Attachments: hadoop-7714-20s-205-mincore.txt
>
>
> This Jira adds a way to log the percentage of pages of a file that were on
> the Linux page cache (when the file is being opened) with the purpose of
> measuring the effect of issuing posix_fadvise (POSIX_FADV_DONTNEED) calls.
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