I was wondering how to update an ear file without stopping the application in a websphere cluster ? with out bring the complete application down.

You may want to take a look here: www.ibm.com/developerworks/websphere/tec...

I copied the below from the above link:

"This function only works well when the update to the application is "compatible" with the prior version of the application. In other words, it must be feasible for both versions of the application to be executing at the same time in the same cluster, and clients should be able to direct requests to either version of the application without failure. Many modifications to applications fall into the category of compatible updates, but it does require consideration by the application developers to know which are and which are not."

The deployments I've performed have required us to stop the application and deploy the application as the changes made by developers typically fall into the "non-compatible" classification.

Erik

Thanks, that helps

You could always investigate WebSphere VE if you're looking to be able to run concurrent versions of the same application and perform cutovers.  But it is a sepperate add on product atop of the ND expense.