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https://issues.apache.org/jira/browse/ACCUMULO-140?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13271581#comment-13271581
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Todd Lipcon commented on ACCUMULO-140:
--------------------------------------
HDFS uses fadvise(DONT_NEED) in addition to sync_file_range to trigger early
writeback. sync_file_range has a flag to enqueue for writeback without forcing
a true fsync, which is nicer on the rest of the system (eg doesn't force a
journal fsync like a normal fsync() does). Check out BlockReceiver.java in
trunk DFS.
> Prevent linux from caching write ahead log files
> ------------------------------------------------
>
> Key: ACCUMULO-140
> URL: https://issues.apache.org/jira/browse/ACCUMULO-140
> Project: Accumulo
> Issue Type: Improvement
> Components: logger
> Reporter: Keith Turner
> Assignee: Eric Newton
> Fix For: 1.5.0
>
>
> While at ApacheCon I attended a talk about Cassandra. The developer
> mentioned using posix_fadvise to prevent linux from storing edit/write ahead
> log data in the page cache. This sounds great. Accumulo can do this for its
> write ahead logs.
> Using posix_fadvise was also mentioned for compactions, this is something
> Accumulo can not do because its compactions read and write to hdfs.
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