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)
******************************************************************************************
# 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 - [email protected]
DL - [email protected]
DXC Technology
-----Original Message-----
From: Christopher Schultz <[email protected]>
Sent: 28 September 2022 00:19
To: Tomcat Users List <[email protected]>
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
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