On 04.10.2009 22:17, Joe Hansen wrote: > I found the following error message in the Apache logs: > [Sat Oct 03 04:10:49 2009] [error] server reached MaxClients setting, > consider raising the MaxClients setting > > Here's a snippet from the httpd.conf, which deals with MaxClients. > <IfModule prefork.c> > StartServers 8 > MinSpareServers 5 > MaxSpareServers 20 > ServerLimit 256 > MaxClients 256 > MaxRequestsPerChild 4000 > </IfModule> > > <IfModule worker.c> > StartServers 2 > MaxClients 150 > MinSpareThreads 25 > MaxSpareThreads 75 > ThreadsPerChild 25 > MaxRequestsPerChild 0 > </IfModule> > > I will watch out for the increase in the number of httpd processes. I > am wondering if I should raise the MaxClients value in prefork.c and > worker.c modules. Can anyone on this forum please explain why new > httpd processes are spawned and why aren't the old processes > terminated?
Likely because requests get stuck (no responses are returned), so the web server waits very long for Tomcat to produce a request and the stream of incoming new requests fill up all available threads in the web server. To find the reason, the thread dumps will be helpful. Regards, Rainer > On Sun, Oct 4, 2009 at 1:45 PM, Joe Hansen <joe.hansen...@gmail.com> wrote: >> Rainer, Thank you so much for your kind reply! >> >> I have increased the java heap size to 512MB (-Xms512m -Xmx512m). I am >> hoping that would fix the issue. I had configured our webserver to use >> Jasig's Central Authentication System (CAS). Recently I increased the >> session timeout from 30 minutes to 4 hours. I am guessing that must >> have had an impact on the number of tickets that the CAS could store >> in the Java's memory space. >> >> I did run the kill -QUIT command against the tomcat process. It did >> generate a huge output in the catalina.out file. I am unable to >> decipher it. I do not want to post it to the mailing list because its >> very long. Would you be able to please tell me what should I be >> looking for within this long thread dump? >> >> Thanks again, Rainer :) >> >> Joe >> >> On Sat, Oct 3, 2009 at 12:24 PM, Rainer Jung <rainer.j...@kippdata.de> wrote: >>> On 03.10.2009 20:07, Joe Hansen wrote: >>>> Hey All, >>>> >>>> I get this error (java.lang.OutOfMemoryError: Java heap space) after >>>> my Apache 2.0/Tomcat 5.5/mod_jk installation has been up and running >>>> for a few hours. This problem started just since two days. Never had >>>> this issue before! >>>> >>>> I have also noticed that as soon as I startup the server, 9 httpd >>>> processes start. Number of httpd processes keep on increasing until I >>>> get the OutOfMemoryError. >>>> $ps -aef | grep httpd >>>> root 31984 1 0 11:23 ? 00:00:00 /usr/sbin/httpd >>>> apache 31987 31984 0 11:23 ? 00:00:00 /usr/sbin/httpd >>>> apache 31988 31984 0 11:23 ? 00:00:00 /usr/sbin/httpd >>>> apache 31989 31984 0 11:23 ? 00:00:00 /usr/sbin/httpd >>>> apache 31990 31984 0 11:23 ? 00:00:00 /usr/sbin/httpd >>>> apache 31991 31984 0 11:23 ? 00:00:00 /usr/sbin/httpd >>>> apache 31992 31984 0 11:23 ? 00:00:00 /usr/sbin/httpd >>>> apache 31993 31984 0 11:23 ? 00:00:00 /usr/sbin/httpd >>>> apache 31994 31984 0 11:23 ? 00:00:00 /usr/sbin/httpd >>> >>> Sounds like requests get stuck or responses are only returned very slowly. >>> >>> I would take thread dumps during the time requests pile up (e.g. httpd >>> process count increases). Thread dumps are generated by "kil -QUIT" >>> against the Tomcat process. Result is written to catalina.out. Always >>> take afew thread dumps shortly after each other, e.g. 3 dumps each 3 >>> seconds apart from the previous one, so that you can find out, if a >>> status in a dump is pure coincidence or lasts for somewhat longer. >>> >>>> $ps -aef | grep tomcat >>>> root 31949 1 43 11:23 pts/0 00:00:58 /usr/java/jdk/bin/java >>>> -Djava.u >>>> il.logging.manager=org.apache.juli.ClassLoaderLogManager >>>> -Djava.util.logging.co >>>> fig.file=/usr/lib/apache-tomcat/conf/logging.properties >>>> -Djava.endorsed.dirs=/u >>>> r/lib/apache-tomcat/common/endorsed -classpath >>>> :/usr/lib/apache-tomcat/bin/boot >>>> trap.jar:/usr/lib/apache-tomcat/bin/commons-logging-api.jar >>>> -Dcatalina.base=/us >>>> /lib/apache-tomcat -Dcatalina.home=/usr/lib/apache-tomcat >>>> -Djava.io.tmpdir=/usr >>>> lib/apache-tomcat/temp org.apache.catalina.startup.Bootstrap start >>> >>> There is no Java memory configuration included above (i.e. al defaults). >>> It might well be, that you have to explicitely set heap size, perm size >>> and if you like also eden and semi spaces. >>> >>>> Can someone on this list please help me resolve this issue. >>>> >>>> Thanks you, >>>> Joe >>> >>> Regards, >>> >>> Rainer --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
