This is the third post in a series of posts treating software quality attributes. Unless your only concern is the scalability of your solution I do recommend that you start by reading the first post of this series.
The scalability quality attribute is something we are only concerned with for server based systems. Scalability is the ability to handle more traffic, more concurrent users, more transactions per unit of time and is therefore related to performance. It is important for your business because if the things we are hoping for happens and your business attracts a lot of customers that produces a huge amount of business transactions you would want your system to be able to handle that increased load. Ideally you would like to be able to handle the new load without having to make a big effort. If you need to redesign the system to be able to handle the increased workload you will lose valuable time (not be able to do all the business you otherwise would have the opportunity to do) and the work of improving the software will itself cost money.
This is the second post in a series of posts treating software quality attributes. Unless your only concern is the performance of your software I do recommend that you start by reading the first post of this series.
The performance of a software is quite simply how fast the software does it’s job. It is commonly measured in response time, that is how long time passes between the initiation of a command until the command has been completed. Performance is often measured in seconds or milliseconds in combination with workload, that is how many concurrent requests the system is handeling. That is the simple part of thinking about performance.