1.内存优化catalina

vi ./bin/catalina.sh
Xms 最小内存，Xmx 最大内存
JAVA_OPTS="-server -Xms2048M -Xmx2048M -XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:+UseCMSCompactAtFullCollection -XX:CMSFullGCsBeforeCompaction=5 -XX:+PrintGCDetails -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=$CATALINA_HOME/logs/heap.dump"

2.并发优化

vi conf/server.xml
${tomcat}/webapps/docs/config/http.html

maxConnections（ 支持最大的并发连接数）：The maximum number of connections that the server will accept and process at any given time
acceptCount（最大的同时接受）:The maximum queue length for incoming connection requests when all possible request processing threads are in use.
maxThreads（该连接最大线程数）：The maximum number of request processing threads to be created by this Connector
minSpareThreads???С??еĹ????̡?The minimum number of threads always kept running

3. 其他优化

$tomcat/webapps/docs/config/host.htmlautoDeployThisflagvalueindicatesifTomcatshouldcheckperiodicallyforneworupdatedwebapplicationswhileTomcatisrunning线上一般采取禁用${tomcat}/webapps/docs/config/http.html
enableLookups(DNS查询,禁用可以提高性能）false

${tomcat}/webapps/docs/config/context.html:
reloadable(catalina自动监视，如果WEB-INF/classes,和/WEB-INF/lib改变了， 线上是绝对不允许开启的，他会带来很重的负载压力)false

• 禁用AJP
  
• 查看tomcat 日志
  tail -f ./log/catalina.out
• iptables -nL
  

-  iptables -F
可以通过/sbin/iptables -F清除所有规则来暂时停止防火墙： (警告：这只适合在没有配置防火墙的环境中，如果已经配置过默认规则为deny的环境，此步骤将使系统的所有网络访问中断)
如果想清空的话，先执行
/sbin/iptables -P INPUT ACCEPT
然后执行
/sbin/iptables -F

4. connector优化apr之安装apr

cd ~/Documents/tar/APR
sudo tar zxvf apr-1.7.0.tar.gz
cd apr-1.7.0
sudo ./configure --prefix=/usr/local/apr
sudo make  
sudo make install  
cd ..
sudo tar -zxvf apr-iconv-1.2.2.tar.gz
cd apr-iconv-1.2.2
sudo ./configure --prefix=/usr/local/apr-iconv --with-apr=/usr/local/apr  
sudo make  
sudo make install
cd ..
apt-get install libexpat1-dev
sudo tar zxvf apr-util-1.6.1.tar.gz  
cd apr-util-1.6.1
sudo ./configure --prefix=/usr/local/apr-util --with-apr=/usr/local/apr
sudo make  
sudo make install 


# tomcat-native.tar.gz
cd /usr/tomcat8/bin
tar zxvf tomcat-native.tar.gz
cd tomcat-native-1.2.28-src
cd native
sudo ./configure --with-apr=/usr/local/apr --with-ssl=/usr/local/openssl --with-java-home=/usr/local/jdk1.8.0_261  CXXFLAGS=-fPIC
sudo make
sudo make install

• 报错 Your version of OpenSSL is not compatible with this version of tcnative
  
• 解决：sudo ./configure --with-apr=/usr/local/apr --with-ssl=/usr/local/openssl --with-java-home=/usr/local/jdk1.8.0_261
  
• 解决：

tar zxvf openssl-1.0.2u.tar.gz
cd ~/Documents/tar/APR


cd openssl-1.0.2u
sudo ./config  --prefix=/usr/local/openssl


修改原来的Makefile文件
sudo vim Makefile 
将原来的：CFLAG=     -DOPENSSL_THREADS
修改为：CFLAG= -fPIC -DOPENSSL_THREADS
也就是添加 -fPIC
执行：
如果你之前执行过sudo ./config 的话，记得这里要make clean 一下哦
sudo make
sudo make install
# 终于搞完，sudo make && make install 不行，必须要分开

5 apr优化之配置优化

• 1 vi conf/server.xml

cd /usr/tomcat8
sudo vim conf/server.xml


<Connector port="8080" protocol="org.apache.coyote.http11.Http11AprProtocol"
connectionTimeout="20000"
redirectPort="8443" />


<Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="off" />

• 2 sudo vim bin/catalina.sh
  JAVA_OPTS="$JAV{A}_{O}PTS-Djava.library.path=/usr/local/apr/lib注意：开启了apr之后，jvm用到的native内存会增大，因此要适当调大metaspace空间，添加JVM选项：-XX:MetaspaceSize=128mJAV{A}_{O}PTS="-server-Xms2048M-Xmx2048M-XX:MetaspaceSize=128M-XX:+HeapDumpOnOutOfMemoryError-XX:HeapDumpPath=$CATALINA_HOME/logs/heap.dump"

ps -ef | grep tomcat
sudo kill -9 pid
sudo sh bin/startup.sh
tail -f ./logs/catalina.out

• 压测一下
  rm -f redis_mq/miaosha_redis_mq.jtl
  ./bin/jmeter.sh -n -t ./redis_mq/miaosha_redis_mq.jmx -l ./redis_mq/miaosha_redis_mq.jtl
• NOTE 可是，我们这里用的好像是spring-boot自带的tomcat呀，并不是我们配的tomcat,那么要是不是需要重新去打war包然后部署？？？呜呜呜