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https://issues.apache.org/jira/browse/ACCUMULO-884?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sean Busbey updated ACCUMULO-884:
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Assignee: (was: Keith Turner)
For whomever takes this on, take a look at Hadoop 2.2.0 [docs on short circuit
local
reads|http://hadoop.apache.org/docs/r2.2.0/hadoop-project-dist/hadoop-hdfs/ShortCircuitLocalReads.html]
for the relevant configs.
A nice to have would be some stats on if reads are actually short circuiting,
in the TServer logs or Monitor. I haven't chased down where to get this
information, sadly.
> Take advantage of short circuit read for local files
> ----------------------------------------------------
>
> Key: ACCUMULO-884
> URL: https://issues.apache.org/jira/browse/ACCUMULO-884
> Project: Accumulo
> Issue Type: Sub-task
> Components: docs
> Reporter: Billie Rinaldi
>
> This is a new feature in hadoop 1.0.x and some versions of 0.22 and 0.23. It
> allows a client to read directly from disk instead of through a DataNode when
> the data is stored locally. Enabling it involves setting two configuration
> parameters, the first in hdfs-site.xml and the second in accumulo-site.xml.
> We should make sure this works with Accumulo and recommend it in the
> documentation.
> - dfs.block.local-path-access.user is the key in datanode configuration to
> specify the user allowed to do short circuit read.
> - dfs.client.read.shortcircuit is the key to enable short circuit read at the
> client side configuration.
> See HDFS-2246 and http://hbase.apache.org/book/perf.hdfs.configs.html for
> more information.
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