Hello! > -----Ursprüngliche Nachricht----- > Von: Kumawat, Priyanka <priyanka.kuma...@dxc.com> > Gesendet: Dienstag, 27. September 2022 21:41 > An: Tomcat Users List <users@tomcat.apache.org> > Betreff: RE: MaxRequestWorkers error > > Hello Christopher , > > Thank you for your assistance !.Please find the mpm event given under > httpd.mpm.conf file on the server as below , the max request worker was > increased 50 more , approx two months before , that time we faced the > same issue with Max request error and Memory got exhausted on server , > the root cause was concluded that time was insufficient memory part of > solution 16GB memory was added to the server along with the Max worker > increase, the tomcat application heap size was also been adjusted - > > But we have started seeing the same kind of problems again , the tomcat > went to crash status with Out of memory errors , and Apache error logs with > Max request errors , whole production environment due to this . > > It occurred twice recently - 16th Sept and 20th Sept. > > ********************************************************** > ************ > Error details - > > : [Tue Sep 20 10:25:23.518687 2022] [mpm_event:error] [pid 29112:tid > 140343038482176] AH00484: server reached MaxRequestWorkers setting, > consider raising the MaxRequestWorkers setting [Tue Sep 20 10:48:08.134955 > 2022] [mpm_event:error] [pid 23940:tid 140413844547328] AH00484: server > reached MaxRequestWorkers setting, consider raising the > MaxRequestWorkers setting > > > [root@ustlswh552 logs]# uptime > 05:08:35 up 72 days, 5:39, 2 users, load average: 0.22, 0.13, 0.07 > > /opt/tomcat/apache-tomcat-8.5.5/logs/localhost.2022-09-16.log > > 16-Sep-2022 15:49:00.672 SEVERE [ajp-nio-8009-exec-117] > org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for > servlet [ws] in context with path [/thq] threw exception [Request processing > failed; nested exception is java.lang.OutOfMemoryError: unable to create > new native thread] with root cause > java.lang.OutOfMemoryError: unable to create new native thread > at java.lang.Thread.start0(Native Method)
How much memory did you configure for your java environment? --> Xmx Parameter If the java process eats too much memory, you can write a memory dump when an OOM exception occurs. E.g. with the parameters: -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/var/logs/javadump.dmp" You can also open a JMX port and inspect the memory using during runtime, e.g. with VirtualVM https://visualvm.github.io/ Other options are: - Activate AccessLog and check the request time. Are they ok or do they take too much time? - Activate tomcat-manager and check the number of active requests and sessions. Are they in the expected range? > > ********************************************************** > ******************************** > > # event MPM > # StartServers: initial number of server processes to start # > MinSpareThreads: minimum number of worker threads which are kept spare > # MaxSpareThreads: maximum number of worker threads which are kept > spare # ThreadsPerChild: constant number of worker threads in each server > process # MaxRequestWorkers: maximum number of worker threads # > MaxConnectionsPerChild: maximum number of connections a server process > serves > # before terminating > <IfModule mpm_event_module> > StartServers 3 > MinSpareThreads 75 > MaxSpareThreads 250 > ThreadsPerChild 50 > MaxRequestWorkers 500 > MaxConnectionsPerChild 0 > </IfModule> > > > Thanks & Regards, > > Priyanka Kumawat | Middleware Admin > T +91.7879364483 > EMail - priyanka.kuma...@dxc.com > DL - ams-leveraged-webadmin-offsh...@dxc.com > > DXC Technology > > > > > > -----Original Message----- > From: Christopher Schultz <ch...@christopherschultz.net> > Sent: 28 September 2022 00:19 > To: Tomcat Users List <users@tomcat.apache.org> > Subject: Re: MaxRequestWorkers error > > Koustav, > > On 9/27/22 11:09, Naha, Koustav wrote: > > We have Tomcat and Apache installed in our production environment > > since > > 5/6 years. Everything was going fine until we started getting > > application not responding status from users, upon checking we found > > out that there was a MaxRequest error as below, > > > > * In Apache log we have found this error. > > > > [Tue Sep 20 10:48:08.134955 2022] [mpm_event:error] [pid 23940:tid > > 140413844547328] AH00484: server reached MaxRequestWorkers setting, > > consider raising the MaxRequestWorkers setting > > > > * we have seen the below error on tomcat logs > > Your attachment has been removed from the mailing list. Can you please > provide a text-only description of the problem? > > > We increased 16gb memory on both servers , now we have 32 Gb memory > in > > each servers. But the issue still is there. > > You could have 1TiB of memory on your server and it would not solve the > issue you are reporting. > > > Suddenly we start getting the error and we have to restart Tomcat and > > Apache. > > > > FAQ: > > > > 1. Need permeant Solution on this as restarting the instances has > > became too frequent these days. > > 2. We increased MaxRequestWorker value 400 from 200. > > > > <IfModule mpm_worker_module> > > StartServers 3 > > MinSpareThreads 75 > > MaxSpareThreads 250 > > ThreadsPerChild 25 > > MaxRequestWorkers 400 > > MaxConnectionsPerChild 0 > > </IfModule> > > Your error message says "[mpm_event:error]" which suggests you are using > the "event" MPM and not the "worker" MPM. You have configured the > "worker" MPM above. Do you have a different config section for > mpm_event_module? > > Another relevant setting is "ServerLimit". > > > 3. Database and network team reported no unusual activity during the > issue. > > Good. That suggests you don't actually have a "problem". You are just hitting > the limits imposed by your configuration. > > > 4. Code is refreshed every month , no issue found on coding side. > > 5. While the issue starts the server becomes low on memory. > > If you are running httpd and Tomcat on the same machine, my guess is that > the memory increase is due to additional load on the application, not the > web server. The web server should be using minimal memory compared to > your application. > > -chris > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > > > > DXC Technology Company -- This message is transmitted to you by or on > behalf of DXC Technology Company or one of its affiliates. It is intended > exclusively for the addressee. The substance of this message, along with any > attachments, may contain proprietary, confidential or privileged information > or information that is otherwise legally exempt from disclosure. Any > unauthorized review, use, disclosure or distribution is prohibited. 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