Chapter 19: Application Scalability
Scalability refers to an application’s ability to add or remove
resources dynamically based on user demand. Throughout this book, you
have learned that one of the greatest advantages of cloud-based applications
is their ability to scale. Anticipating user demand is often a “best
guess” process. In the past, developers had to release site resources (servers,
CPUs, disk space) capable of meeting the anticipated initial user demand,
plus growth. Often developers could not accurately project the demand,
and frequently they released too few or too many resources.
This chapter examines the resource scaling process. By the time you finish this
chapter, you will be able to do the following:
- Define and describe scalability.
- Define and describe the Pareto principle.
- Compare and contrast scaling up and scaling out.
- Understand how the law of diminishing returns applies to the scalability
- Describe the importance of understanding a site’s database read/write ratio.
- Compare and contrast scalability and capacity planning.
- Understand how complexity can reduce scalability.