A better approach to scalability is to have a single object which you can both adjust the resources of (vertical scalability) and adjust the number of instances of (horizontal scalability). That is, you start a single instance with 1 core and 1Gb, then while it's running you crank it up to 2 cores and 2Gb. Eventually you max out at say 8 cores and 16Gb so you need to go horizontal at some point. Rather than create new unlinked instances the idea is that you would simply adjust the