前言
個人記錄一下JVM的最佳配置 附詳解
廢話不多說直接上配置
-server
-Xms2048M ##JVM啓動時申請的初始Heap值，默認爲操作系統物理內存的1/64但小於1G。默認當空餘堆內存大於70%時，JVM會減小heap的大小到-Xms指定的大小，可通過-XX:MaxHeapFreeRation=來指定這個比列。Server端JVM最好將-Xms和-Xmx設爲相同值，避免每次垃圾回收完成後JVM重新分配內存；
-Xmx2048M ##JVM可申請的最大Heap值，默認值爲物理內存的1/4但小於1G，默認當空餘堆內存小於40%時，JVM會增大Heap到-Xmx指定的大小，可通過-XX:MinHeapFreeRation=來指定這個比列。最佳設值應該視物理內存大小及計算機內其他內存開銷而定。
-Xmn256M ##ava Heap Young區大小。整個堆大小=年輕代大小 + 年老代大小 + 持久代大小(相對於HotSpot 類型的虛擬機來說)。持久代一般固定大小爲64m，所以增大年輕代後，將會減小年老代大小。此值對系統性能影響較大，Sun官方推薦配置爲整個堆的3/8
-XX:PermSize=256M ##持久代（方法區）的初始內存大小。
-XX:MaxPermSize=256M ##持久代（方法區）的最大內存大小
-XX:SurvivorRatio=65536 ##SurvivorRatio是eden和survior大小比例 年輕代中Eden區與兩個Survivor區的比值。注意Survivor區有兩個。如：3，表示Eden：Survivor=3：2，一個Survivor區佔整個年輕代的1/5
-XX:MaxTenuringThreshold=0 ##垃圾的最大年齡，代表對象在Survivor區經過10次複製以後才進入老年代。如果設置爲0，則年輕代對象不經過Survivor區，直接進入老年代
-Xnoclassgc ##禁用垃圾回收
-XX:+DisableExplicitGC ##關閉System.gc() 這個參數需要嚴格的測試
-XX:+UseParNewGC ##設置年輕代爲並行收集，JKD5.0以上，JVM會根據系統配置自行設置，所以無需設置此值。
-XX:+UseConcMarkSweepGC ##併發（ConcMarkSweepGC）是指GC運行時，對應用程序運行幾乎沒有影響（也會造成停頓，不過很小而已），GC和app兩者的線程在併發執行，這樣可以最大限度不影響app的運行。
-XX:+UseCMSCompactAtFullCollection ##在Full GC的時候，對老年代進行壓縮整理。因爲CMS是不會移動內存的，因此非常容易產生內存碎片。因此增加這個參數就可以在FullGC後對內存進行壓縮整理，消除內存碎片。當然這個操作也有一定缺點，就是會增加CPU開銷與GC時間
-XX:CMSFullGCsBeforeCompaction=0 ##所以可以通過-XX:CMSFullGCsBeforeCompaction=3 這個參數來控制多少次Full GC以後進行一次碎片整理。
-XX:+CMSClassUnloadingEnabled ##CMSClassUnloadingEnabled，GC也會掃描PermGen，並刪除不再使用的類
-XX:-CMSParallelRemarkEnabled ##手動配置開啓並行標記，節省年輕代標記時間，JDK1.6以前不需要配置，默認開啓
-XX:CMSInitiatingOccupancyFraction=90 ##CMSInitiatingOccupancyFraction是用來計算老年代最大使用率（_initiating_occupancy）的。大於等於0則直接取百分號，小於0則根據公式來計算。這個_initiating_occupancy需要配合-XX:+UseCMSInitiatingOccupancyOnly來使用
-XX:SoftRefLRUPolicyMSPerMB=0 ##SoftRefLRUPolicyMSPerMB代表每一MB空閒內存空間可以允許SoftReference對象存活多久
-XX:+PrintClassHistogram ##在Windows下, 按ctrl-break或Linux下是執行kill -3（發送SIGQUIT信號）時，打印class柱狀圖。 jmap -histo pid也實現了相同的功能。
-XX:+PrintGCDetails ##打印GC詳情
-XX:+PrintGCTimeStamps ##可與-XX:+PrintGC -XX:+PrintGCDetails混合使用
-XX:+PrintHeapAtGC ##打印GC前後的詳細堆棧信息
-Xloggc:log/gc.log ##把相關日誌信息記錄到文件以便分析.與上面幾個配合使用
Catalina.bat配置
@echo off
set JAVA_OPTS=-server -Xms6000M -Xmx6000M -Xmn500M -XX:PermSize=500M -XX:MaxPermSize=500M -XX:SurvivorRatio=65536 -XX:MaxTenuringThreshold=0 -Xnoclassgc -XX:+DisableExplicitGC -XX:+UseParNewGC -XX:+UseConcMarkSweepGC -XX:+UseCMSCompactAtFullCollection -XX:CMSFullGCsBeforeCompaction=0 -XX:+CMSClassUnloadingEnabled -XX:-CMSParallelRemarkEnabled -XX:CMSInitiatingOccupancyFraction=90 -XX:SoftRefLRUPolicyMSPerMB=0 -XX:+PrintClassHistogram -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC -Xloggc:log/gc.log
rem Licensed to the Apache Software Foundation (ASF) under one or more
rem contributor license agreements. See the NOTICE file distributed with
rem this work for additional information regarding copyright ownership.
rem The ASF licenses this file to You under the Apache License, Version 2.0
rem (the "License"); you may not use this file except in compliance with
rem the License. You may obtain a copy of the License at
rem
rem http://www.apache.org/licenses/LICENSE-2.0
rem
rem Unless required by applicable law or agreed to in writing, software
rem distributed under the License is distributed on an "AS IS" BASIS,
rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
rem See the License for the specific language governing permissions and
rem limitations under the License.
rem ---------------------------------------------------------------------------
rem Start/Stop Script for the CATALINA Server
rem
rem Environment Variable Prerequisites
rem
rem Do not set the variables in this script. Instead put them into a script
rem setenv.bat in CATALINA_BASE/bin to keep your customizations separate.
rem
rem WHEN RUNNING TOMCAT AS A WINDOWS SERVICE:
rem Note that the environment variables that affect the behavior of this
rem script will have no effect at all on Windows Services. As such, any
rem local customizations made in a CATALINA_BASE/bin/setenv.bat script
rem will also have no effect on Tomcat when launched as a Windows Service.
rem The configuration that controls Windows Services is stored in the Windows
rem Registry, and is most conveniently maintained using the "tomcatXw.exe"
rem maintenance utility, where "X" is the major version of Tomcat you are
rem running.
rem
rem CATALINA_HOME May point at your Catalina "build" directory.
rem
rem CATALINA_BASE (Optional) Base directory for resolving dynamic portions
rem of a Catalina installation. If not present, resolves to
rem the same directory that CATALINA_HOME points to.
rem
rem CATALINA_OPTS (Optional) Java runtime options used when the "start",
rem "run" or "debug" command is executed.
rem Include here and not in JAVA_OPTS all options, that should
rem only be used by Tomcat itself, not by the stop process,
rem the version command etc.
rem Examples are heap size, GC logging, JMX ports etc.
rem
rem CATALINA_TMPDIR (Optional) Directory path location of temporary directory
rem the JVM should use (java.io.tmpdir). Defaults to
rem %CATALINA_BASE%\temp.
rem
rem JAVA_HOME Must point at your Java Development Kit installation.
rem Required to run the with the "debug" argument.
rem
rem JRE_HOME Must point at your Java Runtime installation.
rem Defaults to JAVA_HOME if empty. If JRE_HOME and JAVA_HOME
rem are both set, JRE_HOME is used.
rem
rem JAVA_OPTS (Optional) Java runtime options used when any command
rem is executed.
rem Include here and not in CATALINA_OPTS all options, that
rem should be used by Tomcat and also by the stop process,
rem the version command etc.
rem Most options should go into CATALINA_OPTS.
rem
rem JAVA_ENDORSED_DIRS (Optional) Lists of of semi-colon separated directories
rem containing some jars in order to allow replacement of APIs
rem created outside of the JCP (i.e. DOM and SAX from W3C).
rem It can also be used to update the XML parser implementation.
rem This is only supported for Java <= 8.
rem Defaults to $CATALINA_HOME/endorsed.
rem
rem JPDA_TRANSPORT (Optional) JPDA transport used when the "jpda start"
rem command is executed. The default is "dt_socket".
rem
rem JPDA_ADDRESS (Optional) Java runtime options used when the "jpda start"
rem command is executed. The default is localhost:8000.
rem
rem JPDA_SUSPEND (Optional) Java runtime options used when the "jpda start"
rem command is executed. Specifies whether JVM should suspend
rem execution immediately after startup. Default is "n".
rem
rem JPDA_OPTS (Optional) Java runtime options used when the "jpda start"
rem command is executed. If used, JPDA_TRANSPORT, JPDA_ADDRESS,
rem and JPDA_SUSPEND are ignored. Thus, all required jpda
rem options MUST be specified. The default is:
rem
rem -agentlib:jdwp=transport=%JPDA_TRANSPORT%,
rem address=%JPDA_ADDRESS%,server=y,suspend=%JPDA_SUSPEND%
rem
rem JSSE_OPTS (Optional) Java runtime options used to control the TLS
rem implementation when JSSE is used. Default is:
rem "-Djdk.tls.ephemeralDHKeySize=2048"
rem
rem LOGGING_CONFIG (Optional) Override Tomcat's logging config file
rem Example (all one line)
rem set LOGGING_CONFIG="-Djava.util.logging.config.file=%CATALINA_BASE%\conf\logging.properties"
rem
rem LOGGING_MANAGER (Optional) Override Tomcat's logging manager
rem Example (all one line)
rem set LOGGING_MANAGER="-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager"
rem
rem TITLE (Optional) Specify the title of Tomcat window. The default
rem TITLE is Tomcat if it's not specified.
rem Example (all one line)
rem set TITLE=Tomcat.Cluster#1.Server#1 [%DATE% %TIME%]
rem ---------------------------------------------------------------------------
setlocal
rem Suppress Terminate batch job on CTRL+C
if not ""%1"" == ""run"" goto mainEntry
if "%TEMP%" == "" goto mainEntry
if exist "%TEMP%\%~nx0.run" goto mainEntry
echo Y>"%TEMP%\%~nx0.run"
if not exist "%TEMP%\%~nx0.run" goto mainEntry
echo Y>"%TEMP%\%~nx0.Y"
call "%~f0" %* <"%TEMP%\%~nx0.Y"
rem Use provided errorlevel
set RETVAL=%ERRORLEVEL%
del /Q "%TEMP%\%~nx0.Y" >NUL 2>&1
exit /B %RETVAL%
:mainEntry
del /Q "%TEMP%\%~nx0.run" >NUL 2>&1
rem Guess CATALINA_HOME if not defined
set "CURRENT_DIR=%cd%"
if not "%CATALINA_HOME%" == "" goto gotHome
set "CATALINA_HOME=%CURRENT_DIR%"
if exist "%CATALINA_HOME%\bin\catalina.bat" goto okHome
cd ..
set "CATALINA_HOME=%cd%"
cd "%CURRENT_DIR%"
:gotHome
if exist "%CATALINA_HOME%\bin\catalina.bat" goto okHome
echo The CATALINA_HOME environment variable is not defined correctly
echo This environment variable is needed to run this program
goto end
:okHome
rem Copy CATALINA_BASE from CATALINA_HOME if not defined
if not "%CATALINA_BASE%" == "" goto gotBase
set "CATALINA_BASE=%CATALINA_HOME%"
:gotBase
rem Ensure that neither CATALINA_HOME nor CATALINA_BASE contains a semi-colon
rem as this is used as the separator in the classpath and Java provides no
rem mechanism for escaping if the same character appears in the path. Check this
rem by replacing all occurrences of ';' with '' and checking that neither
rem CATALINA_HOME nor CATALINA_BASE have changed
if "%CATALINA_HOME%" == "%CATALINA_HOME:;=%" goto homeNoSemicolon
echo Using CATALINA_HOME: "%CATALINA_HOME%"
echo Unable to start as CATALINA_HOME contains a semicolon (;) character
goto end
:homeNoSemicolon
if "%CATALINA_BASE%" == "%CATALINA_BASE:;=%" goto baseNoSemicolon
echo Using CATALINA_BASE: "%CATALINA_BASE%"
echo Unable to start as CATALINA_BASE contains a semicolon (;) character
goto end
:baseNoSemicolon
rem Ensure that any user defined CLASSPATH variables are not used on startup,
rem but allow them to be specified in setenv.bat, in rare case when it is needed.
set CLASSPATH=
rem Get standard environment variables
if not exist "%CATALINA_BASE%\bin\setenv.bat" goto checkSetenvHome
call "%CATALINA_BASE%\bin\setenv.bat"
goto setenvDone
:checkSetenvHome
if exist "%CATALINA_HOME%\bin\setenv.bat" call "%CATALINA_HOME%\bin\setenv.bat"
:setenvDone
rem Get standard Java environment variables
if exist "%CATALINA_HOME%\bin\setclasspath.bat" goto okSetclasspath
echo Cannot find "%CATALINA_HOME%\bin\setclasspath.bat"
echo This file is needed to run this program
goto end
:okSetclasspath
call "%CATALINA_HOME%\bin\setclasspath.bat" %1
if errorlevel 1 goto end
rem Add on extra jar file to CLASSPATH
rem Note that there are no quotes as we do not want to introduce random
rem quotes into the CLASSPATH
if "%CLASSPATH%" == "" goto emptyClasspath
set "CLASSPATH=%CLASSPATH%;"
:emptyClasspath
set "CLASSPATH=%CLASSPATH%%CATALINA_HOME%\bin\bootstrap.jar"
if not "%CATALINA_TMPDIR%" == "" goto gotTmpdir
set "CATALINA_TMPDIR=%CATALINA_BASE%\temp"
:gotTmpdir
rem Add tomcat-juli.jar to classpath
rem tomcat-juli.jar can be over-ridden per instance
if not exist "%CATALINA_BASE%\bin\tomcat-juli.jar" goto juliClasspathHome
set "CLASSPATH=%CLASSPATH%;%CATALINA_BASE%\bin\tomcat-juli.jar"
goto juliClasspathDone
:juliClasspathHome
set "CLASSPATH=%CLASSPATH%;%CATALINA_HOME%\bin\tomcat-juli.jar"
:juliClasspathDone
if not "%JSSE_OPTS%" == "" goto gotJsseOpts
set JSSE_OPTS="-Djdk.tls.ephemeralDHKeySize=2048"
:gotJsseOpts
set "JAVA_OPTS=%JAVA_OPTS% %JSSE_OPTS%"
rem Register custom URL handlers
rem Do this here so custom URL handles (specifically 'war:...') can be used in the security policy
set "JAVA_OPTS=%JAVA_OPTS% -Djava.protocol.handler.pkgs=org.apache.catalina.webresources"
if not "%LOGGING_CONFIG%" == "" goto noJuliConfig
set LOGGING_CONFIG=-Dnop
if not exist "%CATALINA_BASE%\conf\logging.properties" goto noJuliConfig
set LOGGING_CONFIG=-Djava.util.logging.config.file="%CATALINA_BASE%\conf\logging.properties"
:noJuliConfig
if not "%LOGGING_MANAGER%" == "" goto noJuliManager
set LOGGING_MANAGER=-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager
:noJuliManager
rem Configure JAVA 9 specific start-up parameters
set "JDK_JAVA_OPTIONS=%JDK_JAVA_OPTIONS% --add-opens=java.base/java.lang=ALL-UNNAMED"
set "JDK_JAVA_OPTIONS=%JDK_JAVA_OPTIONS% --add-opens=java.base/java.io=ALL-UNNAMED"
set "JDK_JAVA_OPTIONS=%JDK_JAVA_OPTIONS% --add-opens=java.rmi/sun.rmi.transport=ALL-UNNAMED"
rem Java 9 no longer supports the java.endorsed.dirs
rem system property. Only try to use it if
rem JAVA_ENDORSED_DIRS was explicitly set
rem or CATALINA_HOME/endorsed exists.
set ENDORSED_PROP=ignore.endorsed.dirs
if "%JAVA_ENDORSED_DIRS%" == "" goto noEndorsedVar
set ENDORSED_PROP=java.endorsed.dirs
goto doneEndorsed
:noEndorsedVar
if not exist "%CATALINA_HOME%\endorsed" goto doneEndorsed
set ENDORSED_PROP=java.endorsed.dirs
:doneEndorsed
rem ----- Execute The Requested Command ---------------------------------------
echo Using CATALINA_BASE: "%CATALINA_BASE%"
echo Using CATALINA_HOME: "%CATALINA_HOME%"
echo Using CATALINA_TMPDIR: "%CATALINA_TMPDIR%"
if ""%1"" == ""debug"" goto use_jdk
echo Using JRE_HOME: "%JRE_HOME%"
goto java_dir_displayed
:use_jdk
echo Using JAVA_HOME: "%JAVA_HOME%"
:java_dir_displayed
echo Using CLASSPATH: "%CLASSPATH%"
set _EXECJAVA=%_RUNJAVA%
set MAINCLASS=org.apache.catalina.startup.Bootstrap
set ACTION=start
set SECURITY_POLICY_FILE=
set DEBUG_OPTS=
set JPDA=
if not ""%1"" == ""jpda"" goto noJpda
set JPDA=jpda
if not "%JPDA_TRANSPORT%" == "" goto gotJpdaTransport
set JPDA_TRANSPORT=dt_socket
:gotJpdaTransport
if not "%JPDA_ADDRESS%" == "" goto gotJpdaAddress
set JPDA_ADDRESS=localhost:8000
:gotJpdaAddress
if not "%JPDA_SUSPEND%" == "" goto gotJpdaSuspend
set JPDA_SUSPEND=n
:gotJpdaSuspend
if not "%JPDA_OPTS%" == "" goto gotJpdaOpts
set JPDA_OPTS=-agentlib:jdwp=transport=%JPDA_TRANSPORT%,address=%JPDA_ADDRESS%,server=y,suspend=%JPDA_SUSPEND%
:gotJpdaOpts
shift
:noJpda
if ""%1"" == ""debug"" goto doDebug
if ""%1"" == ""run"" goto doRun
if ""%1"" == ""start"" goto doStart
if ""%1"" == ""stop"" goto doStop
if ""%1"" == ""configtest"" goto doConfigTest
if ""%1"" == ""version"" goto doVersion
echo Usage: catalina ( commands ... )
echo commands:
echo debug Start Catalina in a debugger
echo debug -security Debug Catalina with a security manager
echo jpda start Start Catalina under JPDA debugger
echo run Start Catalina in the current window
echo run -security Start in the current window with security manager
echo start Start Catalina in a separate window
echo start -security Start in a separate window with security manager
echo stop Stop Catalina
echo configtest Run a basic syntax check on server.xml
echo version What version of tomcat are you running?
goto end
:doDebug
shift
set _EXECJAVA=%_RUNJDB%
set DEBUG_OPTS=-sourcepath "%CATALINA_HOME%\..\..\java"
if not ""%1"" == ""-security"" goto execCmd
shift
echo Using Security Manager
set "SECURITY_POLICY_FILE=%CATALINA_BASE%\conf\catalina.policy"
goto execCmd
:doRun
shift
if not ""%1"" == ""-security"" goto execCmd
shift
echo Using Security Manager
set "SECURITY_POLICY_FILE=%CATALINA_BASE%\conf\catalina.policy"
goto execCmd
:doStart
shift
if "%TITLE%" == "" set TITLE=Tomcat
set _EXECJAVA=start "%TITLE%" %_RUNJAVA%
if not ""%1"" == ""-security"" goto execCmd
shift
echo Using Security Manager
set "SECURITY_POLICY_FILE=%CATALINA_BASE%\conf\catalina.policy"
goto execCmd
:doStop
shift
set ACTION=stop
set CATALINA_OPTS=
goto execCmd
:doConfigTest
shift
set ACTION=configtest
set CATALINA_OPTS=
goto execCmd
:doVersion
%_EXECJAVA% -classpath "%CATALINA_HOME%\lib\catalina.jar" org.apache.catalina.util.ServerInfo
goto end
:execCmd
rem Get remaining unshifted command line arguments and save them in the
set CMD_LINE_ARGS=
:setArgs
if ""%1""=="""" goto doneSetArgs
set CMD_LINE_ARGS=%CMD_LINE_ARGS% %1
shift
goto setArgs
:doneSetArgs
rem Execute Java with the applicable properties
if not "%JPDA%" == "" goto doJpda
if not "%SECURITY_POLICY_FILE%" == "" goto doSecurity
%_EXECJAVA% %LOGGING_CONFIG% %LOGGING_MANAGER% %JAVA_OPTS% %CATALINA_OPTS% %DEBUG_OPTS% -D%ENDORSED_PROP%="%JAVA_ENDORSED_DIRS%" -classpath "%CLASSPATH%" -Dcatalina.base="%CATALINA_BASE%" -Dcatalina.home="%CATALINA_HOME%" -Djava.io.tmpdir="%CATALINA_TMPDIR%" %MAINCLASS% %CMD_LINE_ARGS% %ACTION%
goto end
:doSecurity
%_EXECJAVA% %LOGGING_CONFIG% %LOGGING_MANAGER% %JAVA_OPTS% %CATALINA_OPTS% %DEBUG_OPTS% -D%ENDORSED_PROP%="%JAVA_ENDORSED_DIRS%" -classpath "%CLASSPATH%" -Djava.security.manager -Djava.security.policy=="%SECURITY_POLICY_FILE%" -Dcatalina.base="%CATALINA_BASE%" -Dcatalina.home="%CATALINA_HOME%" -Djava.io.tmpdir="%CATALINA_TMPDIR%" %MAINCLASS% %CMD_LINE_ARGS% %ACTION%
goto end
:doJpda
if not "%SECURITY_POLICY_FILE%" == "" goto doSecurityJpda
%_EXECJAVA% %LOGGING_CONFIG% %LOGGING_MANAGER% %JAVA_OPTS% %JPDA_OPTS% %CATALINA_OPTS% %DEBUG_OPTS% -D%ENDORSED_PROP%="%JAVA_ENDORSED_DIRS%" -classpath "%CLASSPATH%" -Dcatalina.base="%CATALINA_BASE%" -Dcatalina.home="%CATALINA_HOME%" -Djava.io.tmpdir="%CATALINA_TMPDIR%" %MAINCLASS% %CMD_LINE_ARGS% %ACTION%
goto end
:doSecurityJpda
%_EXECJAVA% %LOGGING_CONFIG% %LOGGING_MANAGER% %JAVA_OPTS% %JPDA_OPTS% %CATALINA_OPTS% %DEBUG_OPTS% -D%ENDORSED_PROP%="%JAVA_ENDORSED_DIRS%" -classpath "%CLASSPATH%" -Djava.security.manager -Djava.security.policy=="%SECURITY_POLICY_FILE%" -Dcatalina.base="%CATALINAY㮹‡zf쀘kۆᬄӫ›[Ĕ˥+5ӫoW⅒û’YﱈC»ۏ𧵳P_–Ï”B֙ÀN#¡œ8 ª솺jw‚ƒÃٰ«•h
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