There are several different types of system test that can be utilised as part of a development, e.g. installation testing, functionality testing, performance testing etc. However, which tests would be relevant for your system depends heavily on what kind of system you are developing.
For example, if you were to build an internet based system where the number of users could expand rapidly, it would be beneficial for you to carry out a scalability test. On the other hand, if you were to develop an embedded system, scalability is probably not something you would need to worry about testing.