Scalability vs performance

• Both are linked

• if the performance of a software system deteriorates rapidly with increasing load (number of users or volume of transactions) prior to reaching the intended load level, then it is not scalable and will eventually underperform

  • The aim is to have the performance of a software system would sustain as a flat curve with increasing load prior to reaching the intended load level

  • classified as type I scalability issue, can be overcome with proper optimizations and tunings

• If the performance of a software system becomes unacceptable when reaching a certain load level with a given environment, but it cannot be improved even with upgraded and/or additional hardware, then it is said that the software is not scalable.

  • type II scalability issue, cannot be overcome without going through some major architectural operations, which should be avoided from the beginning at any cost.

• What performance a software system exhibits often solely depends on the raw speed of the underlying hardware platform, which is largely determined by the central processing unit (CPU) horsepower of a computer.

• What scalability a software system exhibits depends on the scalability of the architecture of the underlying hardware platform