We have a very heavy weight web application which is deployed in Websphere App server 7. But now the architects have decided to move the entire application to Tomcat. I know tomcat is light weight container and pretty efficient, but i am very skeptical about tomcats performance, when used in production environment (considering we get millions of hits and application is huge).
Can anyone let me know the difference between tomcat and websphere in terms of performance. (leave the webserver appserver difference out).
In theory, Tomcat should out-perform WAS. Websphere is a full-stack J2EE server and therefore carries a lot of freight for features such as EJBs, JMS and so forth. However, YMMV.
It's certain that Tomcat has been used for some fairly significant applications, but whether or not it will actually out-perform on your particular set of apps is something that you need to determine by setting up some benchmarks and stress tests.
The bigger challenge is if you're presently using J2EE features that Tomcat doesn't support. In that case, you're going to have to either remove use of those features or include add-ons to make up the difference.
Customer surveys are for companies who didn't pay proper attention to begin with.