ok, I just tried starting tomcat with the default heap size and 18 instances of my webapp and it got OOME just as you see. If I set my heap to -Xms256m -Xmx512m I'm able to load the 18 webapps just fine. the total memory used after all the webapps are loaded is 152Megs.
the total number of webapps is 25 webapps including the default tomcat webapps and a few more. so basically you'll need to set the heap larger enough and it should work. If i do some math, we can calculate a rough estimate for the min heap (154 - 64)/25 = 3.6megs so basically, you'll need to multiply the number of webapps by 4 megs to figure out the heap setting. peter lin On 4/20/05, LeeAnn Pultz <[EMAIL PROTECTED]> wrote: > when you say 50 threads, do you mean 50 separate web applications? > > My concern right now is that we seem to be limited to 17-18 copies of our > web app on a particular installation of tomcat. And that > is just hitting the login page - not doing any work. Practically, for > applications with many users, we may be limited to 7-10 copies of our > application on a tomcat. > > Maybe I'm expecting too much? Perhaps that's a reasonable number of > concurrent webapps that can be run on a tomcat? But if that is the case, > it would be good to know what the limiting factor is, if it's not number of > threads or amount of memory. > > thanks for much for your help! > > > At 05:48 PM 4/20/2005, you wrote: > >ahh ok. .. my confusion. > > > >back to the problem you see. I've tested tomcat with 30-40 threads > >without any problems in the past. Even with heavy weight JSTL tags in > >JSP's, I'm able to go up to 50 threads with tomcat4.1. > > > >I'll try hitting tomcat's status servlet with 50 threads tonight and > >see what happens. > > > > > >peter > > > > > >On 4/20/05, LeeAnn Pultz <[EMAIL PROTECTED]> wrote: > > > I think we've gotten things a bit confused :) > > > > > > The application itself is not thread intensive - our original tests show > > > that each separate copy of the web application started up 3 active > > > threads. > > > > > > Further testing, when we added in debugging code that would spin up dozens > > > of threads just to see if we could cause the tomcat to get the error if we > > > started one application up and had tons of threads, showed that we could > > > get 800+ threads with no problems (no outofmemory errors) and that the > > > problem does not in fact seem to be specifically related to the number of > > > threads the application creates. > > > > > > In fact, regardless of whether each instance of the application spins up 3 > > > threads (real situation) or 10+ (debug code only) threads, we still get > > > the > > > out of memory error not when we hit a certain number of threads, but > > > actually when we hit a certain number of servlets having been initialized. > > > > > > Testing a very simple servlet, I can start up >25 instances of the servlet > > > with no OOM error. > > > Testing our application's servlet, I can only start up 17-18 instances of > > > the servlet before getting an OOM error. > > > > > > At this point I am going through our standard application servlet, trying > > > to isolate what work it does that may cause a problem when we do it 17 or > > > 18 times on one installation of tomcat. > > > > > > > > > At 05:16 PM 4/20/2005, you wrote: > > > >if your application is thread heavy, I would recommend changing it so > > > >that one thread can manage several processes. creating 800+ threads is > > > >going to hit a scalability and reliability wall very quickly. In > > > >general, you want to make sure the number of threads remain constant > > > >under constant load. If it doesn't the server will eventually crash as > > > >you currently see. I'm guessing the application is using threads to > > > >handle async processes, which is good, but spawning new threads with > > > >every request isn't going to work. > > > > > > > >hope that helps > > > > > > > >peter > > > > > > > > > > > >On 4/20/05, LeeAnn Pultz <[EMAIL PROTECTED]> wrote: > > > > > We tried a new test :) > > > > > > > > > > We added code that spins up 8 threads inside just a plain servlet that > > > > > doesn't do anything else. When I fire up 10 different "instances" > > of that > > > > > servlet, I get hundreds of threads printing out as being active - > > and no > > > > > out of memory errors. > > > > > > > > > > So we added the same code to our (slightly more complex) application > > > > > servlet, and did the same thing. Now the reported number of threads > > > > > is > > > > > much higher, but I still get an OutOfMemory error at the same > > number of new > > > > > instances fired up (between 17-18 sites started up). > > > > > > > > > > Active Threads : WHEN STARTING INIT() 617 > > > > > [GC 57193K->46096K(129792K), 0.0353880 secs] > > > > > [GC 57936K->47554K(129792K), 0.0238210 secs] > > > > > [Full GC 49312K->47441K(129792K), 0.6546550 secs] > > > > > [Full GC 47732K->47129K(129792K), 0.7706500 secs] > > > > > [Full GC 48310K->47256K(129792K), 0.6425030 secs] > > > > > [Full GC 47276K->47263K(129792K), 0.6445770 secs] > > > > > [Full GC 47263K->47263K(129792K), 0.6368020 secs] > > > > > [Full GC 47263K->47241K(129792K), 0.7775600 secs] > > > > > java.lang.OutOfMemoryError > > > > > [Full GC 47295K->47242K(129792K), 0.6301470 secs] > > > > > [Full GC 47248K->47245K(129792K), 0.6451800 secs] > > > > > [Full GC 47257K->47250K(129792K), 0.6454320 secs] > > > > > [Full GC 47271K->47262K(129792K), 0.7056980 secs] > > > > > java.lang.OutOfMemoryError > > > > > java.lang.OutOfMemoryError > > > > > > > > > > So it looks like it isn't just a thread issue. > > > > > > > > > > If I fire up the simple servlet 18 times, I don't get the > > error. In fact, > > > > > I can then go on to fire up our main servlet another 17-18 times > > before we > > > > > get the OutOfMemory error - this time at 844 threads before it dies. > > > > > > > > > > There must be something else going on within our application that is > > > > > consuming something that the simple servlet doesn't. > > > > > > > > > > If anyone has any suggestions on other things that I could check for ? > > > > > Someone said OOM errors can mean out of file descriptors as well? > > > > > > > > > > thanks for all your help so far - I'm really hoping we can figure > > this out! > > > > > > > > > > > > > > > > > >--------------------------------------------------------------------- > > > >To unsubscribe, e-mail: [EMAIL PROTECTED] > > > >For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > LeeAnn Pultz > > > ExtraView Corporation > > > [EMAIL PROTECTED] > > > 831-461-7100 x115 > > > > > > --------------------------------------------------------------------- > > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > > > >--------------------------------------------------------------------- > >To unsubscribe, e-mail: [EMAIL PROTECTED] > >For additional commands, e-mail: [EMAIL PROTECTED] > > LeeAnn Pultz > ExtraView Corporation > [EMAIL PROTECTED] > 831-461-7100 x115 > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
