Hi Joe. Well, heres how I run it - and remember this is all dependent on the beakdown of requirements of the following:
1. Web app memory needs - how memory intensive are your web apps within Tomcat going to be? 2. Concurrent connections (tcp threads) for incoming requests - how busy will the web apps be? 3. Are you running DB connections? Are you using a Connection pool? How long will each db connection take to return? 4. Are you running OTHER applications/servers on the server which will require memory? E.g. RDBMS Server 5. Always be aware that the native OS will also need memory - thus you cannot just give it all to Tomcat! So, heres one of my scenarios: Server: Quad Xeon 2GB RAM OS: Windows 2000 Server (32 bit) Applications/Servers: Tomcat 5.0.28 (with 40 web apps/contexts/classloaders) MSSQL Server 2000 My Tomcat runtime switches are as follows: -Xms768m //assign all the JVM heap at startup to 768mb -Xmx768m //assign max JVM heap -Xss128k //set the native thread stack size memory allocation down from windows def of 1024kb - very useful -XX:+UseParallelGC //parralel GC - makes use of the multiple processors -XX:MaxPermSize=256m //up the perm gen space (used for classloading etc) from def 64mb - also useful with lots of web apps -XX:+DisableExplicitGC //don't let the System.gc() be called as it could cuse 'pause the world's I also limit the amount of RAM that MSSQL can have to 640mb - and have also set the memory allocation size per sql connection down from 1024kb to 512kb (SQL Server setting) - this is however due to my running MSSQL Server on the same box and may not apply. I have thus left some RAM for the OS to use where required - this should not be ignored. I found that this is a pretty stable setup - with my only problem occurring occasionally when I get a MAJOR spike in concurrent requests. I plan to upgrade to a 64bit OS soon and to up the SQL RAM allocation as my problem lies there - it sometimes has issues with memory! It should be noted that my web apps can be fairly SQL intensive - I do have VM level caching but alas not all of it.... Anyway - I do hope that helps! Other areas you could look into is the number of concurrent requests Tomcat serves (set at a Connector level) - as too many will cause memory issues under load, while too few will cause visitors to be rejected/wait for response! Anyway, take care, Carl -----Original Message----- From: Joe Reger, Jr. [mailto:[EMAIL PROTECTED] Sent: 03 December 2005 13:19 To: Tomcat Users List Subject: Re: How much memory will Tomcat 5.5/Java 5 support? > Are you running a 64bit or 32bit OS? If 32bit the JVM will not be > able to assign higher that 2gb for a single process (which includes > system overheads etc). Hi Carl - I'm 32 bit right now. I'll check the archive for past posts. How would you go about using more of the memory that I have on the server? Can I run two Tomcat services and cluster? Thanks for the feedback and help! Joe --------------------------------------------------------------------- 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]
