What is the recommended procedure for deployment of Java Web App in tomcat? Drop the uncompressed directory or just drop the war? Im asking because the war is compressed, doesnt it have a performance cost?
By default, Tomcat will uncompress your WAR during deployment, so the only penalty you will pay is for the time to decompress the WAR file at that time (which shouldn't be much).
I find WAR files to be more convenient for deployment because you just copy a single file instead of doing a recursive-scp or something like that.
Deployment performance cost should not be a thing to worry about.
The only way to answer your questions is to make a real test, 'cause it depends on your application size, number of files in it, server parameters and many other things.
It didn't have any noticeable performance as far as I remember but also have in mind that you need to construct and redeploy the whole WAR file each time you want to push an update (even for just one .class)