2009/10/5 prashant sharma <psharma_...@yahoo.com>: > Tomcat: 5.0. That's old, and no longer supported. Why are you using this version? (And exactly which version of 5.0 are you using, by the way?)
> OS: Windows Server HPC edition. 32- or 64-bit? I ask because the maximum contiguous memory you'll get in 32-bit is somewhere around 1400 Mbytes - the numbers vary depending on exactly which Microsoft OS. > JVM: 5.0 That's also old. Why are you using this version? > There is one basic doubt that I have. When we load/stress our Tomcat server, > we hit thresholds mentioned below once in a while. The root of the problem is > that when I increase the clients, I start getting a connection refused error > on the server side. This is because the server hits the maximum request > processing thread limit. The other problems are connected to it: > > -Max threads (tomcat): > > As mentioned above, this is the root of the problem. To solve this problem, I > increase the max threads in server.xml. Then I get the Out of stack space > exception. > > -Stack Memory: > > Now for this I tried a couple of things > a) Reduce the stack size allotted per thread so that more threads can be > spawned in the allotted stack space.I believe that the default is around > 320K/ thread. I set it to 128K in the JVM options (Xss). > b) Reduce the heap size. I did this because as per my understanding the > memory alloted to a process is divided among heap and stack. So probably > reducing the heap size makes more memory available for stack. Don't know if > this is correct? It certainly makes more memory available for the OS stack. > Now once in a while I get Out of memory exception for heap space. > > -Heap Memory: > > Can somebody advise as to what are the solutions for these sort of problems > other than reducing the memory/thread consumption, of our application logic. > I mean are there techniques that can be applied on tomcat/JVM/OS level to > make more threads/memory available to the tomcat process? OS: Use a 64-bit OS. Add RAM to the server. Use anything other than 32-bit Windows in order to get a larger contiguous heap space. If you absolutely have to use Windows, and it absolutely has to be the 32-bit version, use the /3GB switch *with extreme care* - read up on *exactly* what it does and what will break before enabling it. JVM: You've done the main thing, which is to reduce the stack depth per thread. Tomcat: Memory and CPU usage is generally better in newer versions. Other tunings are very much application-specific, I suspect. However, I think we all know what the underlying problem is: your application will not reliably fit in the available space with the load you're putting on it during the test. Add more space, load-balance onto multiple machines of the size you have, tune the app, or reduce the scale of your load test if it's deliberately a long way above your target load. - Peter --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
