Thanks a Lot Mark On Mon, Dec 9, 2019 at 2:22 PM Mark Thomas <ma...@apache.org> wrote:
> On 09/12/2019 06:41, Jayaram Ponnusamy wrote: > > Thanks for your Valuable Comments: > > We are using Apache Tomcat/8.0.50 and Mod_JK mod_jk/1.2.28 > > > > The Above configuration made by some consultant. We are in the > situation to > > correct all the things to make it for high availability. > > Also we are in the process of upgrading the apache to 2.4.25 with mod_jk/ > > 1.2.42. And Event MPM instead of Prefork. > > > > Please let us know do we need to use worker MPM also or EVENT MPM is > fine? > > If Event MPM with below Configuration then how many concurrent users can > > access the site and what are the relevant changes needs to be done on > > Tomcat Side? > > On Tomcat Servers We have 16GB RAM with 8CPU [Two Nodes] > > > > # event MPM > > <IfModule event.c> > > StartServers 1 > > ServerLimit 7 > > MinSpareThreads 250 > > MaxSpareThreads 2500 > > ThreadsPerChild 500 > > ThreadLimit 500 > > MaxRequestWorkers 3500 > > MaxConnectionsPerChild 0 > > </IfModule> > > > > > > # Tomcat Configuration > > <Connector port="9090" protocol="HTTP/1.1" redirectPort="8443" > > URIEncoding="UTF-8" emptySessionPath="true" maxThreads="600" > > minSpareThreads="10" connectionTimeout="-1" /> > > <Connector port="8009" protocol="AJP/1.3" redirectPort="8443" > > URIEncoding="UTF-8" maxThreads="600" minSpareThreads="100" > > connectionTimeout="20000" acceptCount="2000" /> > > > > > > # Tomcat Configuration > > -Xms2048M -Xmx6144M -XX:PermSize=1024m -XX:MaxPermSize=2048m > > > > > > > > > > On Thu, Dec 5, 2019 at 7:27 PM Christopher Schultz < > > ch...@christopherschultz.net> wrote: > > > > Jayaram, > > > > On 12/5/19 03:19, Jayaram Ponnusamy wrote: > >>>> We are using apache 2.2.21 on RHEL6.9 and in Backend we are using > >>>> Tomcat AppServer with JavaBased CMS. Our Server Architecture is > >>>> *(F5 [For Load Balance] -> Apache WebServer [For Redirection & URL > >>>> Mapping] -> Tomcat AppServer [Running a Java Based CMS]).* > > > > That version of Apache httpd is pretty old and unsupported. RHEL 6.9 > > is also out of support (if I'm reading their Wikipedia page > > correctly). You may want to upgrade everything while you are looking > > at all this. > > > >>>> We are using Apache to connect Tomcat by MOD_JK and mapping the > >>>> URL (Attached VirtualHost.conf), and No applications/code are > >>>> running on WebServers. > >>>> > >>>> 1. Two TomcatServers (8 CPU & 16GB RAM on Each Servers) 2. Two > >>>> WebServers (4 CPU & 8GB RAM on Each Servers) > >>>> > >>>> *PROBLEM:* When the Child Process count is reached / crossed 200 > >>>> like below then site is not accessible > > > > Do you mean that new connections from httpd -> Tomcat cannot be made? > > > >>>> when the child processes reached 300 or More than site crashed > > > > Please define "crashed". Got an exception? JVM crash (with hs_pid* > > file)? Kernel panic? > > > >>>> and then we bring the site back by restarting Tomcat & Apache > >>>> HTTP. > > > > Do you need to restart httpd? Or only Tomcat? Or will restarting httpd > > work? > > > >>>> Kindly please check my configuration and help to allow at-least > >>>> 500 concurrent users. > >>>> > >>>> *CONFIGURATION:* * httpd.conf* <IfModule prefork.c> StartServers > >>>> 80 ServerLimit 3500 MaxClients 3500 MaxRequestsPerChild 0 > >>>> </IfModule> <IfModule worker.c> StartServers 6 MaxClients 230 > >>>> MinSpareThreads 75 MaxSpareThreads 150 ThreadsPerChild 25 > >>>> MaxRequestsPerChild 0 </IfModule> > > > > Which MPM are you actually using? You have listed both prefork and > > worker. AFAICT you have to pick one at runtime. > > > > For prefork, the maximum number of connections you should expect to be > > made to each Tomcat backend is 3500 (the value of MaxClients). > > > > For worker, the maximum number of connections you should expect to be > > made to each Tomcat backend is 230. > > > >>>> *Tomcat:* <Connector port="9090" protocol="HTTP/1.1" > >>>> redirectPort="8443" URIEncoding="UTF-8" emptySessionPath="true" > >>>> maxThreads="600" minSpareThreads="10" connectionTimeout="-1" /> > >>>> <Connector port="8009" protocol="AJP/1.3" redirectPort="8443" > >>>> URIEncoding="UTF-8" maxThreads="600" minSpareThreads="100" > >>>> connectionTimeout="20000" acceptCount="2000" /> > > > > Note that AJP connections are expected to be persistent; they don't > > close when the request has completed. They don't even really do "keep > > alive" in the same sense as HTTP keepalive. It's more like "always > > keepalive". Once an httpd process opens a connection to a Tomcat > > instance, that connection will remain open for quite a while as long > > as requests continue to be made. > > > > If you are using prefork MPM, the the version of Tomcat you are using > > is critical to understanding what is happening, here. If you are using > > a BIO-based connector, then you will need to increase the number of > > threads on each Tomcat server from 600 to 3500. > > > > If you are using the worker MPM, then your Tomcat should be able to > > handle the 230 maximum connections configured there. > > TL;DR - Try switching to the NIO AJP connector on Tomcat. > > Take a look at this session I uploaded from TomcatCon London. You > probably want to start around 35:00 and the topic of thread > exhaustion. > > https://youtu.be/2QYWp1k5QQM > > Mark > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > > -- *Thanks & Regards,* *Jayaram Ponnusamy*
