title: Does it make sense to deploy more instance of Tomcat on a VM?
body: <p>Similar question to, "Does it make sense to have multiple tomcat instances on the same server?" but in this case the Tomcats are running on a VM.</p>
  
  <p>I know the answer probably is "it depends," but I'd like to explore the issue. When does it make sense? What are the VM specific considerations?</p>
  
  <p>Reasons I've heard:
  1) JVMs are somehow limited in their ability to use the resources available. So allocating more than one instance of tomcat will make better use of resources. Not sure that this is a good reason. Is this one of those things that was once true, but is no longer true? 
  2) If one instance of tomcat fails, the other can take over. </p>
  
  <p>Downsides:
  There's more overhead when you have multiple versions and greater complexity.</p>
  
  <p>If we need load balancing is it "better" to just put the second tomcat in another VM?</p>