Thanks again, to make things clear. When I meant default, what is the default min and max that is given to an application if there nothing defined in the JVM ?
In my case, the Tomcat is running on windows and I don't have setenv.bat or sentenv.sh or even catalina.bat and catalina.conf does not have the OPT config for min and max. HTH Thank you -Gokul -----Original Message----- From: Olaf Kock [mailto:tom...@olafkock.de] Sent: Sunday, February 21, 2016 3:04 PM To: Tomcat Users List <users@tomcat.apache.org> Subject: Re: Tomcat memory grep mx bin/* found only settings in setenv.sh in my installation - this lets me state that there are no defaults: setenv.sh is not contained in the distribution but will be read in case it's found in the file system. Thus there's no tomcat default that I'm aware of. Anybody who distributes tomcat with a setenv.sh might have a sensible default for their embedded application, but the raw distribution AFAIK has none. Safe assumption should be: Whatever the JVM thinks is appropriate is the default. Create a setenv.sh or setenv.bat and set CATALINA_OPTS to the desired value, e.g. "-Xms 2048m -Xmx2048m" (but there will probably be more settings, e.g. for tuning the garbage collector... (apologies in case this goes out after the problem has long been solved: I'm in a hotel that blocks SMTP and have to find a way to send mail from here) Olaf Am 21.02.2016 um 18:23 schrieb Gokul.Baskaran: > Question was for Java 7 > > It is a Tomcat / Application question as well, as memory default can be > configured in the application config. > > I totally agree that the best practice is to set the Xms and -Xmx. As am > going to change the config, I would curious to know if the tomcat ui or the > catalina does not have a Xms and -Xmx, would it default to 400MB? I read this > in another forum. > > -Gokul > > > -----Original Message----- > From: Olaf Kock [mailto:tom...@olafkock.de] > Sent: Sunday, February 21, 2016 3:14 AM > To: Tomcat Users List <users@tomcat.apache.org> > Subject: Re: Tomcat memory > > This is rather a Java than a tomcat question: > > The JVM allocates memory based on whatever default your current JVM > version decides (you don't mention what version of Java you're on) > > From a text on > http://docs.oracle.com/javase/7/docs/technotes/guides/vm/gc-ergonomics > .html > that's linked from my Java's manpage: > > *initial heap size* > > Larger of 1/64th of the machine's physical memory on the machine > or some reasonable minimum. Before J2SE 5.0, the default initial > heap size was a reasonable minimum, which varies by platform. > You can override this default using the |-Xms| command-line option. > > *maximum heap size* > > Smaller of 1/4th of the physical memory or 1GB. Before J2SE 5.0, > the default maximum heap size was 64MB. You can override this > default using the |-Xmx| command-line option. > > *Note:* The boundaries and fractions given for the heap size are > correct for J2SE 5.0. They are likely to be different in subsequent > releases as computers get more powerful. > > Note that this is from JavaSE7 and even mentions 5 - with more power there > comes more initial and maximum memory defaults. > > I'm not aware of the actual development of the default memory - mostly > because I consider it good practice to know what an application uses > and provide it explicitly, rather than relying on defaults. (and > frankly, on the applications that I see, the default typically is not > even enough - let alone a good basis for tuning) > > While we're at it: For production systems I consider it good practice to set > -Xms and -Xmx to the same value. Reason: If you don't have enough memory > available, you want to know this when the process starts, not days later when > it tries to allocate "the rest" - typically sunday night at 3am. > > Olaf > > Am 21.02.2016 um 03:39 schrieb Gokul.Baskaran: >> Hi, >> >> I am currently running tomcat 7 in Windows 2012. >> >> The current JVM Heap memory parameters are set to empty, does the JVM Heap >> memory utilize the entire memory of the OS or does it default to a specific >> memory number? >> >> Thank you >> -Gokul >> >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
