Minimum and recommended requirement for Tomcat 7 or Tomcat 6
What is the minimum and recommended requirements for tomcat 6 or Tomcat 7. Please provide memory requirement, Disk Space Requirement and Processor requirement ?
Answer
Tomcat 6/7 itself can run in about 12MiB of heap. Tomcat 7.0.35 takes up exactly 13412390 bytes on your disk with no applications installed and no log files. If you don't install any web applications or write any log files, Tomcat requires 13MiB of disk space. Processor requirements are all dependent upon the JVM. I suspect that a JVM requires a 32-bit processor with at least one core.
So, basically anything that you can successfully boot that was manufactured in the last 20 years should be able to run Tomcat 6 or 7.
Recommended system configuration: most cores, most memory, and most disk space you can afford.
Obviously, nobody can give you any good advice without any input. I've seen web applications that run extremely well under expected load on a single core with 512MiB of memory installed and minimal disk usage. On the other hand, I've seen multi-core machines with 32GiB of memory fall-over because of improper configuration, badly-written software and inadequate capacity-planning.
EDIT 2016-07-13
For Tomcat 8 running on Oracle Java 8, a Tomcat server running only a trivial web applications starts up inside of ~24MiB. Tomcat 8 is required to process a lot more things on startup and when deploying a web application, so additional heap is necessary. It may be possible to pare this down, but I just took an existing Tomcat instance I had and started it with no web applications deployed (except a trivial one to report memory usage) to see what it looked like.