How Well Server Scales or Replicates to Multiple Machines?

Applicable when our needs grow beyond one JVM.
We can think of a load-balancing server which distributes clients among a set of machines. We would need to divide our objects among the machines.
The Account is easy. Since there are many of them we can re-write our launcher to register some of them with one machine, some with another, and so on.
The Bank is very hard to spread out since two clients with two Banks (from different servers) could be trying to access the same account.
Advantage: Account