RE: Tomcat scalability
You would be better off to use a load balancer in front of a cluster of Tomcat servers. It gives you very good scalability, with good fault tolerance. -Original Message- From: ryan [mailto:rsburgess;shaw.ca] Sent: 03 November, 2002 12:39 AM To: [EMAIL PROTECTED] Subject: Tomcat scalability 1. For a project my company is working on we have transactions requirements of 1600 transactions per second. The transactions consists of processing a servlet in Tomcat, doing a database call and then displaying the results to the user so the effective number of transactions Tomcat has to process is actually greater than 1600. Can Tomcat cope with 1600 requests in a second(a 4 processor Sunfire machine will be used)? Based upon our current application architecture(our java application has tomcat running inside it), 1600 request per second means we may have 1600 threads open simultaneously. 2. From one article I read at linux journal, Tomcat 3 didn't scale very well with multiple processors because of JVM issues. -- To unsubscribe, e-mail: mailto:tomcat-dev-unsubscribe;jakarta.apache.org For additional commands, e-mail: mailto:tomcat-dev-help;jakarta.apache.org -- To unsubscribe, e-mail: mailto:tomcat-dev-unsubscribe;jakarta.apache.org For additional commands, e-mail: mailto:tomcat-dev-help;jakarta.apache.org
Re: Tomcat scalability
That's a tough question to answer, and pretty much the only way you're going to be able to tell is to try it. Here's a few suggestions of things to think about: The first question you might want to ask is can your database handle 1600 transactions per second? If not (and even if it can) you may want to consider whether some kind of caching could help you if the data is largely static. This could be caching of the data itself, or something as simple as caching the pages themselves, with some scheme to flush the cache if the data changes. If your data is not very static, then this wouldn't be as helpful of course. If it's possible on the OS you are using, I'd be tempted to run 4 copies of Tomcat, and dedicate a processor to each one. It's a lot harder to write code that will run reliably on a MP machine than on a SP one, and it seems that Tomcat has a few issues in that regard. Also, remember, it's unlikely you'll ever have that many threads open at once - if you are actually handling 1600 requests/second then each request is, on average, taking less than a millisecond to complete, so you won't have too many overlapping requests. If you can work out how long it takes to process one request, then you'll have a best-case scenario of how many you can handle. In practice, it will be less of course, due to overhead in handling multiple requests at once. -- Rob ryan [EMAIL PROTECTED]To: [EMAIL PROTECTED] a cc: Subject: Tomcat scalability 03/11/2002 02:39 AM Please respond to Tomcat Developers List 1. For a project my company is working on we have transactions requirements of 1600 transactions per second. The transactions consists of processing a servlet in Tomcat, doing a database call and then displaying the results to the user so the effective number of transactions Tomcat has to process is actually greater than 1600. Can Tomcat cope with 1600 requests in a second(a 4 processor Sunfire machine will be used)? Based upon our current application architecture(our java application has tomcat running inside it), 1600 request per second means we may have 1600 threads open simultaneously. 2. From one article I read at linux journal, Tomcat 3 didn't scale very well with multiple processors because of JVM issues. -- To unsubscribe, e-mail: mailto:tomcat-dev-unsubscribe;jakarta.apache.org For additional commands, e-mail: mailto:tomcat-dev-help;jakarta.apache.org -- To unsubscribe, e-mail: mailto:tomcat-dev-unsubscribe;jakarta.apache.org For additional commands, e-mail: mailto:tomcat-dev-help;jakarta.apache.org
Re: Tomcat scalability
One good rule of thumb is not to solve problems that don't exist. Your first task is to set up a server and hit it with something a good 20%-50% more demanding than your expected load. There exist several automated tools to do this. One is JMeter at http://jakarta.apache.org/jmeter/index.html . Then, have a look at your actual performance and work on the bottlenecks that arise. If your application is spending most of its time waiting for database results, cache them. If your application is spending most of its time creating and destroying objects, consider pooling. If your app is choking on serving up 1600 images a second, use a web server such as Apache in front of Tomcat. That will help with static requests (images, static HTML) even with a single Tomcat server doing the servlet work. -- Ryan Hoegg ISIS Networks http://www.isisnetworks.net [EMAIL PROTECTED] wrote: That's a tough question to answer, and pretty much the only way you're going to be able to tell is to try it. Here's a few suggestions of things to think about: The first question you might want to ask is can your database handle 1600 transactions per second? If not (and even if it can) you may want to consider whether some kind of caching could help you if the data is largely static. This could be caching of the data itself, or something as simple as caching the pages themselves, with some scheme to flush the cache if the data changes. If your data is not very static, then this wouldn't be as helpful of course. If it's possible on the OS you are using, I'd be tempted to run 4 copies of Tomcat, and dedicate a processor to each one. It's a lot harder to write code that will run reliably on a MP machine than on a SP one, and it seems that Tomcat has a few issues in that regard. Also, remember, it's unlikely you'll ever have that many threads open at once - if you are actually handling 1600 requests/second then each request is, on average, taking less than a millisecond to complete, so you won't have too many overlapping requests. If you can work out how long it takes to process one request, then you'll have a best-case scenario of how many you can handle. In practice, it will be less of course, due to overhead in handling multiple requests at once. -- Rob 1. For a project my company is working on we have transactions requirements of 1600 transactions per second. The transactions consists of processing a servlet in Tomcat, doing a database call and then displaying the results to the user so the effective number of transactions Tomcat has to process is actually greater than 1600. Can Tomcat cope with 1600 requests in a second(a 4 processor Sunfire machine will be used)? Based upon our current application architecture(our java application has tomcat running inside it), 1600 request per second means we may have 1600 threads open simultaneously. 2. From one article I read at linux journal, Tomcat 3 didn't scale very well with multiple processors because of JVM issues. -- To unsubscribe, e-mail: mailto:tomcat-dev-unsubscribe;jakarta.apache.org For additional commands, e-mail: mailto:tomcat-dev-help;jakarta.apache.org
Re: Tomcat scalability
Quoting Jon Scott Stevens [EMAIL PROTECTED]: on 2002/11/3 2:24 PM, Bojan Smojver [EMAIL PROTECTED] wrote: I know you have a much better machine, but 1600 transactions does seem a bit high. Not for porn. Nah... they wouldn't use Java for that. They'd use Porn Hypertext Processor (PHP) ;-) Bojan -- To unsubscribe, e-mail: mailto:tomcat-dev-unsubscribe;jakarta.apache.org For additional commands, e-mail: mailto:tomcat-dev-help;jakarta.apache.org
