Tomcat调优总结

Tomcat默认能够使用的内存为128MB，在较大型的应用项目中，这点内存是不够的，需要调大。 

Windows下，在文档/bin/catalina.bat，Unix下，在文档/bin/catalina.sh的前面，增加如下配置： 

JAVA_OPTS=’-Xms【初始化内存大小】 -Xmx【能够使用的最大内存】’ 

需要把这个两个参数值调大。例如： 

JAVA_OPTS=’-Xms256m -Xmx512m’ 

表示初始化内存为256MB，能够使用的最大内存为512MB。 

另外需要考虑的是Java提供的垃圾回收机制。虚拟机的堆大小决定了虚拟机花费在收集垃圾上的时间和频度。收集垃圾能够接受的速度和应用有关，应该通过分析实际的垃圾收集的时间和频率来调整。假如堆的大小很大，那么完全垃圾收集就会很慢，但是频度会降低。假如您把堆的大小和内存的需要一致，完全收集就很快，但是会更加频繁。调整堆大小的的目的是最小化垃圾收集的时间，以在特定的时间内最大化处理客户的请求。在基准测试的时候，为确保最好的性能，要把堆的大小设大，确保垃圾收集不在整个基准测试的过程中出现。 

假如系统花费很多的时间收集垃圾，请减小堆大小。一次完全的垃圾收集应该不超过 3-5 秒。假如垃圾收集成为瓶颈，那么需要指定代的大小，检查垃圾收集的周详输出，研究 垃圾收集参数对性能的影响。一般说来，您应该使用物理内存的 80% 作为堆大小。当增加处理器时，记得增加内存，因为分配能够并行进行，而垃圾收集不是并行的。 

<?xml version=’1.0′ encoding=’utf-8′?>
<!–
  Licensed to the Apache Software Foundation (ASF) under one or more
  contributor license agreements.  See the NOTICE file distributed with
  this work for additional information regarding copyright ownership.
  The ASF licenses this file to You under the Apache License, Version 2.0
  (the “License”); you may not use this file except in compliance with
  the License.  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an “AS IS” BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
–>
<!– Note:  A “Server” is not itself a “Container”, so you may not
     define subcomponents such as “Valves” at this level.
     Documentation at /docs/config/server.html
 –>
<Server port=”8005″ shutdown=”SHUTDOWN”>

  <!–APR library loader. Documentation at /docs/apr.html –>
  <Listener className=”org.apache.catalina.core.AprLifecycleListener” SSLEngine=”on” />
  <!–Initialize Jasper prior to webapps are loaded. Documentation at /docs/jasper-howto.html –>
  <Listener className=”org.apache.catalina.core.JasperListener” />
  <!– JMX Support for the Tomcat server. Documentation at /docs/non-existent.html –>
  <Listener className=”org.apache.catalina.mbeans.ServerLifecycleListener” />
  <Listener className=”org.apache.catalina.mbeans.GlobalResourcesLifecycleListener” />

  <!– Global JNDI resources
       Documentation at /docs/jndi-resources-howto.html
  –>
  <GlobalNamingResources>
    <!– Editable user database that can also be used by
         UserDatabaseRealm to authenticate users
    –>
    <Resource name=”UserDatabase” auth=”Container”
              type=”org.apache.catalina.UserDatabase”
              deion=”User database that can be updated and saved”
              factory=”org.apache.catalina.users.MemoryUserDatabaseFactory”
              pathname=”conf/tomcat-users.xml” />
  </GlobalNamingResources>

  <!– A “Service” is a collection of one or more “Connectors” that share
       a single “Container” Note:  A “Service” is not itself a “Container”, 
       so you may not define subcomponents such as “Valves” at this level.
       Documentation at /docs/config/service.html
   –>
  <Service name=”Catalina”>
  
    <!–The connectors can use a shared executor, you can define one or more named thread pools–>
    <Executor name=”tomcatThreadPool” namePrefix=”catalina-exec-” 
        maxThreads=”500″ minSpareThreads=”50″ maxIdleTime=”60000″/>
    
    
    <!– A “Connector” represents an endpoint by which requests are received
         and responses are returned. Documentation at :
         Java HTTP Connector: /docs/config/http.html (blocking & non-blocking)
         Java AJP  Connector: /docs/config/ajp.html
         APR (HTTP/AJP) Connector: /docs/apr.html
         Define a non-SSL HTTP/1.1 Connector on port 8080
    –>
        <!–
    <Connector port=”8080″ protocol=”HTTP/1.1″ 
               connectionTimeout=”20000″ 
               redirectPort=”8443″ maxThreads=”500″/>
        –>
    <!– A “Connector” using the shared thread pool–>
    <Connector executor=”tomcatThreadPool”
               port=”8080″ protocol=”HTTP/1.1″ 
               connectionTimeout=”20000″ 
               redirectPort=”8443″ maxKeepAliveRequests=”1″/>
    <!– Define a SSL HTTP/1.1 Connector on port 8443
         This connector uses the JSSE configuration, when using APR, the 
         connector should be using the OpenSSL style configuration
         described in the APR documentation –>
    <!–
    <Connector port=”8443″ protocol=”HTTP/1.1″ SSLEnabled=”true”
               maxThreads=”150″ scheme=”https” secure=”true”
               clientAuth=”false” sslProtocol=”TLS” />
    –>

    <!– Define an AJP 1.3 Connector on port 8009 –>
    <Connector port=”8009″ protocol=”AJP/1.3″ redirectPort=”8443″ />

    <!– An Engine represents the entry point (within Catalina) that processes
         every request.  The Engine implementation for Tomcat stand alone
         analyzes the HTTP headers included with the request, and passes them
         on to the appropriate Host (virtual host).
         Documentation at /docs/config/engine.html –>

    <!– You should set jvmRoute to support load-balancing via AJP ie :
    <Engine name=”Catalina” defaultHost=”localhost” jvmRoute=”jvm1″>         
    –> 
    <Engine name=”Catalina” defaultHost=”localhost”>

      <!–For clustering, please take a look at documentation at:
          /docs/cluster-howto.html  (simple how to)
          /docs/config/cluster.html (reference documentation) –>
      <!–
      <Cluster className=”org.apache.catalina.ha.tcp.SimpleTcpCluster”/>
      –>       

      <!– The request dumper valve dumps useful debugging information about
           the request and response data received and sent by Tomcat.
           Documentation at: /docs/config/valve.html –>
      <!–
      <Valve className=”org.apache.catalina.valves.RequestDumperValve”/>
      –>

      <!– This Realm uses the UserDatabase configured in the global JNDI
           resources under the key “UserDatabase”.  Any edits
           that are performed against this UserDatabase are immediately
           available for use by the Realm.  –>
      <Realm className=”org.apache.catalina.realm.UserDatabaseRealm”
             resourceName=”UserDatabase”/>

      <!– Define the default virtual host
           Note: XML Schema validation will not work with Xerces 2.2.
       –>
      <Host name=”localhost”  appBase=”webapps”
            unpackWARs=”true” autoDeploy=”true”
            xmlValidation=”false” xmlNamespaceAware=”false”>

        <!– SingleSignOn valve, share authentication between web applications
             Documentation at: /docs/config/valve.html –>
        <!–
        <Valve className=”org.apache.catalina.authenticator.SingleSignOn” />
        –>

        <!– Access log processes all example.
             Documentation at: /docs/config/valve.html –>
        <!–
        <Valve className=”org.apache.catalina.valves.AccessLogValve” directory=”logs”  
               prefix=”localhost_access_log.” suffix=”.txt” pattern=”common” resolveHosts=”false”/>
        –>

      </Host>
    </Engine>
  </Service>
</Server>

参考文档:Tomcat调优配置技巧集锦 

如何修改tomcat生成的日志权限

bin/catalina.sh 

不过我们通常只用后三位，同样对应属主属组以及其他用户的权限，例如你的账号umask值为0022（可直接通过umask命令查看）， 此时你创建的文件权限默认为644（文件初始的最高权限为666，umask设置为022，那么最终的权限为：6-0,6-2,6-2=644。 当然有人说文件的权限最高是777，是的没错，但我们说的是默认权限，默认权限是由umask决定的， umask设置为000时文件的权限就是666，文件夹权限777），此时创建的目录权限为755（目录的最高权限为777，umask设置为022， 那么最终的权限为7-0,7-2,7-2=755）

# Set UMASK unless it has been overridden
if [ -z "$UMASK" ]; then
    UMASK="0022"
fi
umask $UMASK