TomcatExpert

Simultaneous Users

How many "simultaneous users" can a Tomcat server support and where do I find this setting? I've read on the internet that Tomcat is limited to 15 "simultaneous users" and that Tomcat supports "unlimited numbers" of users. What's the real story?

asked by johnv

question

Tomcat doesn't have such a setting and you shouldn't trust everything you read on the internet!

A limitation like 15 simultaneous users would make the large scale, high availability Tomcat deployments that are already powering banks, government applications and large corporations completely impossible. On the Apache Tomcat Users mailing list, for example, we see people fairly frequently who are debugging their applications under load tests simulating thousands of concurrent users.

One of the advantages of using software like Tomcat is that it provides the Servlet Spec environment, (which is usually enough to support most applications with a few Apache Commons libraries or the use of frameworks like Struts and Spring), but it's lightweight and uses comparatively little in the way of system resources itself.

The amount of concurrent users will depend on the server hardware (processors, memory), the types of resources being used within the application and what your application is actually doing. A fictional application which generates PDF reports on demand from large amounts of data, taking minutes for each request is going to need substantially more server resources to support a similar number of users to an application which is serving largely static or cached resources.

In Tomcat versions 6.0 and up, the best way to configure the number of threads the Connector uses is via the Executor element. http://tomcat.apache.org/tomcat-6.0-doc/config/executor.html

The default setting for the maxThreads attribute is 200, which should be enough to get most applications started. In fact, in my experience you'll need to add more servers to scale up because of application memory usage before the maxThreads attribute gets too high.

So, to answer each question: Tomcat is not limited to 15 users; it will support however many concurrent users your application(s) can support.

answer

answered by pidster on August 3, 2010 10:02 AM

Stuart Williams is a Senior Consultant for the SpringSource Division of VMware, Inc. (NYSE: VMW). Stuart has been a Tomcat user for 6 years and is a regular contributor to the Apache Tomcat Users mailing list, and is also a committer on the Apache Amber OAuth project.

Comments

Tomcat 7.0.34 concurrent requestes

Hi,

We have developed a web application.We are using tomcat 7.0.32 as web server.

•The client needs configuration for supporting 5K-10K customers.
The Application server configuration provided by the client has been mentioned below.
The webserver used for the application is Apache tomcat 7.0.34.

Can you please let us know is this configuration will liable for supporting 5k -10k customers or do we need to improve the configuration for better performance.?

Application Sever :M1 Medium Instance
3.75 GiB memory
2 EC2 Compute Unit (1 virtual core with 2 EC2 Compute Unit)
410 GB instance storage
32-bit or 64-bit platform
I/O Performance: Moderate
EBS-Optimized Available: No
API name: m1.medium

Can anyone help me please?

Thanks,
Ann

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