If you ever worked in a software company, you most likely heard once someone saying “Hey, we can’t do this, because this doesn’t scale!”

I believe “Scalability” must be on the top 10 list of the “buzz words” most used in the software industry.

It is usually considerated as a killing argument in a conversation. “If something doesn’t scale, then we don’t want it.”

One of the things that fascinates me about “buzz word” is that most of the time it has so many different definitions. Everyone has a tendency to give it a personal definition. Often, people will be too shy to ask for a clear definition. Therefore, it makes it even harder to be able to really understand what underlies behind it. So, What does Scalability mean ?

In telecommunications and software engineering, scalability is a desirable property of a system, a network, or a process, which indicates its ability to either handle growing amounts of work in a graceful manner or to be readily enlarged. (Source: Wikipedia)

In my humble opinion, there are a few important keywords (in bold) in this definition that should be kept in mind when thinking about scalability.

I recently watched that video (I love google tech talks) from Cuong Do Cuong given during a quite old conference in Seattle (in 2007). Cuong is an engineering manager at Google (YouTube).  “He was part of the engineering team that scaled the YouTube software and hardware infrastructure from its infancy to its current scale. Prior to YouTube/Google, he held various software development and management positions at PayPal and Inktomi.”

Cuong shares with us some his experiences, the different issues related to scalability he and the team faced. I hope you will enjoy it as much as I did.