How to realize concurrency Optimization in Tomcat

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There are three common operation modes of Tomcat, which are bio,nio,apr. Apr is recommended for production environment.

Install APR

[root@liuyazhuang ~] # yum-y install apr apr-devel openssl-devel [root@liuyazhuang ~] # tar zxvf tomcat-native.tar.gz [root@liuyazhuang ~] # cd tomcat-native-1.1.24-src/jni/native [root@liuyazhuang native] #. / configure-with-apr=/usr/bin/apr-1-config-with-ssl=/usr/include/openssl/ [root@liuyazhuang native] # make & & make install

After the installation is complete, the following prompt appears

Libraries have been installed in: / usr/local/apr/lib

After a successful installation, you also need to set the environment variable for tomcat by adding one line to the catalina.sh file:

Add under this paragraph:

= # OS specific support. $var _ must_ be set to either true or false. Cygwin=false darwin=false = CATALINA_OPTS= "- Djava.library.path=/usr/local/apr/lib"

Modify the corresponding conf/server.xml on the 8080 side

Protocol= "org.apache.coyote.http11.Http11AprProtocol"

After starting tomcat, check the log

More TOMCAT_HOME/logs/catalina.out Apr 07, 2017 11:49:12 AM org.apache.catalina.core.AprLifecycleListener init INFO: Loaded APR based Apache Tomcat Native library 1.1.31 using APR version 1.3.9. Apr 07, 2017 11:49:12 AM org.apache.catalina.core.AprLifecycleListener init INFO: APR capabilities: IPv6 [true], sendfile [true], accept filters [false], random [true]. Apr 07, 2017 11:49:12 AM org.apache.catalina.core.AprLifecycleListener initializeSSL INFO: OpenSSL successfully initialized (OpenSSL 1.0.1e 11 Feb 2013) Apr 07, 2017 11:49:13 AM org.apache.coyote.AbstractProtocol init INFO: Initializing ProtocolHandler ["http-apr-8080"] Apr 07, 2017 11:49:13 AM org.apache.coyote.AbstractProtocol init INFO: Initializing ProtocolHandler ["ajp-apr-8009"] Apr 07, 2017 11:49:13 AM org.apache.catalina.startup.Catalina load INFO: Initialization processed in 1125 ms

Tomcat optimization

1.JVM tuning

Add the following statement to TOMCAT_HOME/bin/catalina.sh, depending on the situation.

Add it to the end of the CATALINA_OPTS above:

JAVA_OPTS=-Xms512m-Xmx1024m-XX:PermSize=512M-XX:MaxNewSize=1024m-XX:MaxPermSize=1024m

Detailed explanation of parameters

-Xms JVM initializes the heap memory size

-maximum memory of the Xmx JVM heap

-Xss thread stack size

-XX:PermSize JVM non-heap initial memory allocation size

-XX:MaxPermSize JVM non-heap maximum memory

Recommendations and considerations:

The-Xms and-Xmx options are set to the same heap memory allocation to avoid adjusting the heap size after each GC. Heap memory is recommended to account for 60% / 80% of memory. Non-heap memory is non-recyclable memory, depending on the project. The thread stack size is recommended to be 256k.

The 32GB memory configuration is as follows:

JAVA_OPTS=-Xms20480m-Xmx20480m-Xss1024K-XX:PermSize=512m-XX:MaxPermSize=2048m

two。 Turn off DNS reverse query

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