I just got my own question answered whether connection_pool_size sets a pool per server process.
"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." This still leaves me with the question; 1200 (apache connections) is still bigger than 600 (15 x 10 server processes x 4 tomcat nodes) 2010/11/5 Marc Wilmots <desj...@gmail.com> > Rainer, that's very true. > So I am wondering...If 1200 > 200 (Tomcat maxThreads), then what would be > the right way to solve this? Imagine that 2 Tomcats would crash, that would > leave me with 1200 > 400. I can't just raise the maxThreads to 600 for each > Tomcat, as that would probably perform even worse (I'm thinking about > excessive context switching, etc). > > The best solution would be to enable DisableReuse as Mark stated, although > I'm afraid that would be too big of a performance hit. > The other option would be to configure the connection_pool_size, according > to Mladen's link. Although, this last one isn't very clear to me either. I > state from the URL Mladen passed: > > *"There are 4 JBoss servers each containing 1 JBoss instance(s) giving a > total of 4 mod_jk workers* > > *Given the ThreadsPerChild of 60 and the MaxClients (600) / > ThreadsPerChild (60) = Processes (10) and with 2 Apache instance(s) then > the connection_pool_size has been best determined to be 15* > > *The total Jboss threads 1600 are > the total Apache threads 1200. The > mod_jk connection_pool_size was determined to be 15 via the math 600Apache > MaxClients / > 4 total Jboss instances 150 threads per JBoss which will be equal to or > less than the maxThreads 400 150 / 10 Apache server processes to get the > connection_pool_size of 15. in Jboss. Take this number"* > > I'm wondering, setting connection_pool_size 15, wouldn't this mean that the > maximum number of connections being handled by tomcat at one time is limited > to 15?? Or would there be a pool per Apache server process? Which would mean > 150 connections (10 server processes) per Tomcat. If so, then this would > total 600 connections (4 Tomcats). > > 1200 > 600. Same problem, right? > > 2010/10/28 Rainer Jung <rainer.j...@kippdata.de> > > On 26.10.2010 20:36, Marc Wilmots wrote: >> >>> 2010/10/26 Mladen Turk<mt...@apache.org> >>> >>> On 10/26/2010 02:47 PM, Marc Wilmots wrote: >>>> >>>> Hi Experts, >>>>> >>>>> I have the following setup: >>>>> >>>>> Apache1 >>>>> / \ >>>>> Apache2 Apache3 >>>>> \ / >>>>> Tomcat1 >>>>> >>>>> All Apaches are version 2.2.3 (RedHat) >>>>> Apache2 and Apache3 loadbalance Tomcat1 (6.0.18) with mod_jk (2.2.28). >>>>> >>>>> In idle state the AJP connector of Tomcat1 only has 7 active >>>>> connections. >>>>> After launching a stress test of Tomcat1, it's AJP connector has >>>>> reached >>>>> maxThreads (200). After the stress test has finished, there are still >>>>> 200 >>>>> active connections in the AJP connector. >>>>> >>>>> Because of this, apache2 and apache2 cannot receive any heartbeat >>>>> message >>>>> anymore from the AJP connector and mark Tomcat1 as dead. I can access >>>>> perfectly through port 8080, so Tomcat1 isn't dead at all! >>>>> >>>>> >>>>> You have a usual setup problem where the number of connections >>>> in httpd fronting tomcat is too high for a tomcat. >>>> And you don't have any mechanism for limiting those connections. >>>> >>>> Sorry, I realize I had to mention I have a total of 4 Tomcats, which in >>>> >>> total make up a maxThreads of 800 (200 each). >>> The Apaches have a maxClients of each 600 (1200 total). >>> >>> 1200> 1000, thus your theory is probably right. However, I'm just >>> wondering... I read that when Tomcat reaches the max number of >>> connections, >>> just rejects new connections (I'm omitting the backlog on purpose). >>> >> >> Yes. >> >> But your calculation above is not right. Each Apache will connect to each >> Tomcat. So from the point of view of one Tomcat, it has 200 threads, but >> 1200 posible incoming connections from the Apache Servers. So it is not 1200 >> > 800 but 1200 > 200! >> >> Regards, >> >> Rainer >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org >> For additional commands, e-mail: users-h...@tomcat.apache.org >> >> >
