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Posted to commits@hbase.apache.org by st...@apache.org on 2012/09/15 02:04:25 UTC
svn commit: r1384977 - /hbase/trunk/src/docbkx/performance.xml
Author: stack
Date: Sat Sep 15 00:04:25 2012
New Revision: 1384977
URL: http://svn.apache.org/viewvc?rev=1384977&view=rev
Log:
Added link to read short circuit dev conversation into read short circuit footnote
Modified:
hbase/trunk/src/docbkx/performance.xml
Modified: hbase/trunk/src/docbkx/performance.xml
URL: http://svn.apache.org/viewvc/hbase/trunk/src/docbkx/performance.xml?rev=1384977&r1=1384976&r2=1384977&view=diff
==============================================================================
--- hbase/trunk/src/docbkx/performance.xml (original)
+++ hbase/trunk/src/docbkx/performance.xml Sat Sep 15 00:04:25 2012
@@ -200,14 +200,16 @@
<title>Leveraging local data</title>
<para>Since Hadoop 1.0.0 (also 0.22.1, 0.23.1, CDH3u3 and HDP 1.0) via
<link xlink:href="https://issues.apache.org/jira/browse/HDFS-2246">HDFS-2246</link>,
-it is possible for the DFSClient to take a shortcut and
+it is possible for the DFSClient to take a "short circuit" and
read directly from disk instead of going through the DataNode when the
data is local. What this means for HBase is that the RegionServers can
read directly off their machine's disks instead of having to open a
socket to talk to the DataNode, the former being generally much
faster<footnote><para>See JD's <link xlink:href="http://files.meetup.com/1350427/hug_ebay_jdcryans.pdf">Performance Talk</link></para></footnote>.
+Also see <link xlink:href="http://search-hadoop.com/m/zV6dKrLCVh1">HBase, mail # dev - read short circuit</link> thread for
+more discussion around short circuit reads.
</para>
-<para>To enable "shortcircuit" reads, you must set two configurations.
+<para>To enable "short circuit" reads, you must set two configurations.
First, the hdfs-site.xml needs to be amended. Set
the property <varname>dfs.block.local-path-access.user</varname>
to be the <emphasis>only</emphasis> user that can use the shortcut.