Your system might work flawlessly at the beginning, but when the usage increases, the system resources will be stressed more and more causing your system to become slower. If the load becomes to high your solution might even start to produce error messages and itâ€™s really time to expand your system.
If we need to expand our system to meet our business needs we are talking about scalability. We can expand by adding extra hardware, like extra servers, or by upgrading the existing hardware, like adding extra hard drives or CPU power. Note that we are not talking about optimizing our application’s software.
If we take a look at BizTalk Server we talk about scalability when we want to scale BizTalk to increase our throughput or if we want to reduce latency times. The BizTalk Server architecture enables us to scale-up and to scale-out.
Adding extra hardware to our environment like servers to spread the work load. We can double the throughput by adding an identical server.
Of course we can keep the solution inside the same box. We might try to improve our system by upgrading from a single-core CPU system to a dual-core CPU.
MSDN provides an useful piece of documentation on the situations and ways we can scale BizTalk.