Hi, I'm actually working on a production platform to make some benchmarks and there is an important latency mainly because of sockets renewal.
The platform is set up with 4 front servers hosting 1 apache process and 24 middle servers hosting 4 tomcat instances. Thus there is 4 apaches and 96 tomcat workers in the mod_jk worker configuration file. The previous apache non working configuration was: <IfModule worker.c> StartServers 5 MaxClients 8192 ServerLimit 137 MinSpareThreads 25 MaxSpareThreads 60 ThreadsPerChild 60 MaxRequestsPerChild 1000 </IfModule> I found an apache MPM worker configuration which has successfully passed the benchmarks: <IfModule worker.c> StartServers 16 MaxClients 8192 ServerLimit 34 MinSpareThreads 25 MaxSpareThreads 150 ThreadsPerChild 256 MaxRequestsPerChild 0 </IfModule> Reading the tomcat worker documentation, I saw that the connection_pool_size parameter is equal to ThreadsPerChild by default. This defines the number of connections made to the AJP backend that are maintained as a connection pool. It will limit the number of those connection that each web server child process can made. So I first conclude that: 1 Apache Child process = 1 mod_jk connection pool shared between N threads and connection_pool_size = N where N is the value of ThreadsPerChild apache parameter Thus in the example above we could have maximum 34 mod_jk connection pools (1 per Apache child) and connection_pool_size = 256 -> 8704 connections But I found the configuration site below: http://lbconfig.appspot.com/?lb=mod_jk&v=1.2.27%20or%20less&nca=4&ncj=4&nai=4&nji=24&njips=4&f=true&c=false&lr=false&lrl=&mpm=Worker which explain us that there is a connection_pool_size for each worker. Thus 1 Apache Child process can handle X threads and indirectly Y workers so there is Y mod_jk connection pools per apache child and connection_pool_size = X. Thus in the example above we could have maximum 34 (ServerLimit) * 96 (tomcat workers) mod_jk connection pools and connection_pool_size = 256 -> 835584 connections Does anyone can elucidate that question? Apache ThreadPerChild parameter should be superior or equal to the number of mod_jk tomcat workers? Thanks for help, David Ramblewski Ce message et les pièces jointes sont confidentiels et réservés à l'usage exclusif de ses destinataires. Il peut également être protégé par le secret professionnel. Si vous recevez ce message par erreur, merci d'en avertir immédiatement l'expéditeur et de le détruire. L'intégrité du message ne pouvant être assurée sur Internet, la responsabilité du groupe Atos Origin ne pourra être recherchée quant au contenu de ce message. Bien que les meilleurs efforts soient faits pour maintenir cette transmission exempte de tout virus, l'expéditeur ne donne aucune garantie à cet égard et sa responsabilité ne saurait être recherchée pour tout dommage résultant d'un virus transmis. This e-mail and the documents attached are confidential and intended solely for the addressee; it may also be privileged. If you receive this e-mail in error, please notify the sender immediately and destroy it. As its integrity cannot be secured on the Internet, the Atos Origin group liability cannot be triggered for the message content. Although the sender endeavours to maintain a computer virus-free network, the sender does not warrant that this transmission is virus-free and will not be liable for any damages resulting from any virus transmitted. --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
