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Posted to commits@accumulo.apache.org by ec...@apache.org on 2013/04/26 16:27:43 UTC
svn commit: r1476220 - /accumulo/branches/1.5/docs/administration.html
Author: ecn
Date: Fri Apr 26 14:27:43 2013
New Revision: 1476220
URL: http://svn.apache.org/r1476220
Log:
ACCUMULO-1351 document timeout settings for hdfs
Modified:
accumulo/branches/1.5/docs/administration.html
Modified: accumulo/branches/1.5/docs/administration.html
URL: http://svn.apache.org/viewvc/accumulo/branches/1.5/docs/administration.html?rev=1476220&r1=1476219&r2=1476220&view=diff
==============================================================================
--- accumulo/branches/1.5/docs/administration.html (original)
+++ accumulo/branches/1.5/docs/administration.html Fri Apr 26 14:27:43 2013
@@ -98,5 +98,51 @@ false, then accumulo will only use memor
not use more than what -Xmx is set to. In this case the
tserver.memory.maps.max setting should be 75% of the -Xmx setting.
+<h3>Swappiness</h3>
+
+<p>The linux kernel will swap out memory of running programs to increase
+the size of the disk buffers. This tendency to swap out is controlled by
+a kernel setting called "swappiness." This behavior does not work well for
+large java servers. When a java process runs a garbage collection, it touches
+lots of pages forcing all swapped out pages back into memory. It is suggested
+that swappiness be set to zero.
+
+<pre>
+ # sysctl -w vm.swappiness=0
+ # echo "vm.swappiness = 0" >> /etc/sysctl.conf
+</pre>
+
+<h3>Hadoop timeouts</h3>
+
+<p>In order to detect failed datanodes, use shorter timeouts. Add the following to your
+hdfs-site.xml file:
+
+<pre>
+
+ <property>
+ <name>dfs.socket.timeout</name>
+ <value>3000</value>
+ </property>
+
+ <property>
+ <name>dfs.socket.write.timeout</name>
+ <value>5000</value>
+ </property>
+
+ <property>
+ <name>ipc.client.connect.timeout</name>
+ <value>1000</value>
+ </property>
+
+ <property>
+ <name>ipc.clident.connect.max.retries.on.timeouts</name>
+ <value>2</value>
+ </property>
+
+
+
+</pre>
+
+
</body>
</html>