One of the key characteristics of cloud-based services is the flexibility it offers to avail required resources as and when there is a business need. The need to engage more resources could arise when business expands or when there is a diversification in company portfolio. Whatever be the reason, there are 3 important things to consider while scaling your cloud presence.
 The first important thing is the Capacity. Before increasing the capacity, businesses should understand the requirement of a single instance of the application; In other words, the capacity required when one user utilizes the application. By performing a load test on a single instance of the application and by measuring the resource consumption like memory, CPU utilization etc., the overall capacity requirement can be calculated through projections.
 The second thing is Availability. The application should not crash even if the number of users trying to access it at a particular point of time is very high. Depending on the package chosen, there is a limit to the number of users who can access the application at any given point of time. When this number is nearing the threshold, an alert should be given to the application provider to manage all the users. When the number of users increases over a period of time, it is wise to opt for a higher package that can accommodate more users and ensure the availability of the application to all of them.
 Performance is another important thing that determines the user experience. Here, performance refers to the round trip time (RTT) for an average request / response from a user. The time taken for the application to respond once the user makes a request (i.e. RTT) provides a clear picture about the application performance. The RTT should be consistent for all users even if the maximum number of users accesses it at a particular point of time. If there is any lag in the response time, then the company should think of scaling it to a higher package, so that they can accommodate all users with consistent performance.
All the above three factors are important as they are inseparable and they impact each other in reality. High capacity utilization degrades performance, availability impacts both capacity and performance and poor performance can degrade capacity.