A single bank operation is a several successive operations of data collection and aggregation from a dozen of initial sources - bank automated systems (called AS) such as:
currency exchange rates
- terrorists' database
- and so on
Requests from one AS goes thru enterprise serial bus (IBM Websphere MQ) to the input queue of the second AS, third AS, and further...
You must be sure that the system and the bus can deal with a huge load.
80..100 million transactions per day, dozens of systems, thousands of unique types of operations.
To conduct the load test, the stubs is needed for all involved parts of the system. Only than the request chain will not break.
Universal stub system needed, to emulate any AS in the shortest term of time. And any stub need to provide throughput at least 1000 operations per second.
I will tell you how we did it.