Hi, > a) are you sure ? Since, commercially speaking, I can't imagine what > benefit they would get from this (as opposed to e.g. limiting the amount > of RAM or disk space), I tend to have a doubt.
unfortunately I am ... and yes, I agree - this option is absolutely mindless ... > Also, I am not sure but it seems to me that if there is a maximum number of > processes built-in, that should be a configurable OS setting in Linux. This option is set by the VM Hostingsystem - so I can't change this on os level. > b) thread != process. See e.g. > http://manpages.ubuntu.com/manpages/intrepid/man7/pthreads.7.html I know the difference - so to get my process count I use pstree. As I Know pstree counts processes (parent and child) - right? > > Thats quite a huge issue, because I want to operate two virtual hosts: > > > > apache-dev -- tomcat-dev -- mysql > > apache-www -- tomcat-prod -- mysql > > > > * mysql uses 50 threads in total > > * apache uses 5 > > * tomcat_prod - 109 > > * tomcat_dev - 73 > > c) again, are you not confusing threads and processes ? > For Apache httpd e.g., depending on the MPM model used, you will be using > either processes (pre-fork MPM) or threads, or both. No I use prefork - but I know the other mpm options to so I will switch to threading as soon as I understand the tomcat behaviour. > In a prefork MPM, that can indeed lead to up to 51 simultaneous *processes* > (aka 1 main Apache + 50 Apache "children"), IF you have as many > simultaneous requests being processed. I run many sites with Maxclients > 20, or less (specially for development sites). Maxclinets is defined for two v-hosts - prod with 40 and dev with 3 so your right, I can save 7 processes here :-) > > * mod_jk connection_pool_size (3/40), socket_keepalive=false > > There is not really any benefit to have more Apache-Tomcat connections, > than your MaxClients setting above. (3/40) means 3 for dev and 40 for prod. > > * server.xml: > > > > <Executor name="tomcatDevThreadPool" namePrefix="catalina-exec-" > > > > daemon="false" maxThreads="(3/40)" maxSpareThreads="5" > > > > minSpareThreads="1"/> > > Ideally, you need as many threads as there can be individual *tomcat* > requests in the course of being processed at the same time. There is no > benefit in having (or starting) more than that. > Since presumably all requests pass first through Apache before there reach > Tomcat, you need as a maximum number of Tomcat threads, the same number ax > MaxClients in Apache. Your right - I will decrease my maxclients for 7. But how can I limit the number of tomcat-processes? Even if I assume that a java thread is mapped to one os-process I don't understand the 109 tomcat processes in a nearly idle tomcat with maxthreads 4 configured at his only connector! > > <Connector executor="tomcatDevThreadPool" port="8009" > > > > protocol="AJP/1.3" URIEncoding="UTF-8"/> ... > > Any idea how to cope with this silly process limit? > > Change the provider ? Yes, thats what I will do - but in meantie I've to cope with this one. Kind regards, Michael
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