What is Scalability in cloud?

When we study AWS cloud, We often come across the term 'Scalability'. So here I try to explain it in simple form for my students, if it helps.

example1: Assume you are shifting your house and you have a small box to pack things. But the small box is not good enough to keep things.

No problem ! you replace the small box with the big box. This is an example of Scale-up or Scalability.

example2: Lets say you have one big box. But you have much more household items to pack.

No problem ! you add 20 more big boxes.

This is also an example of Scalability.

example3: You want to fill the bucket with water that flows from the pipe but the water that flows out every second is very little because the pipe is just 2 mm thick.

No problem, you get a fatter pipe of 20 mm. It will push out more water per second.

This is also an example of Scalability.

example4: I have a cupboard storage with two shelf's to keep all my stuff in the house. But the storage is not enough. So I plan to increase my storage by adding more shelves.

All the above are examples of scalability. 

In AWS Cloud, we have EC2 virtual machines that run your application. Every machine has a certain number of processor, certain amount of memory and certain amount of EBS (Elastic Block Storage) storage attached to it.

Just like example1 where your small box had to be replaced by big box, AWS cloud allows us to move from small machine to a bigger machine. Bigger machine would mean more processor, more memory.

Similar to example4, the cupboard shelves scaling, Elastic Block Storage size can be increased in AWS cloud. Example, you can increase your storage from 20GB to 60 GB.

Similar to example3, the water pipe example, you can increase the amount of reads and writes to your database. Example you can increase the throughput of your reads/writes to your DynamoDB database.

Similar to example2, adding more big boxes to manage the multiple household items, we can increase the number of machines to handle the application load.

For example, initially I may have 2 machines managing the same website. But when there is a cricket match between India and Pakistan, lot of people are downloading live cricket match video on their browser. All the load actually falls back on your 2 machines but your 2 machines are not enough and hence we have to quickly add maybe 100 more machines to telecast the cricket match.

The beauty of AWS cloud is that it can scale various services anytime, any quantity, in any aws region of the world as per the needs.

I hope next time you hear the word Scalability, you understand that something can grow/shrink or something can increase/decrease quickly anytime, in any quantity, anywhere.

Let me know if you want me to explain any other cloud term :-)

#aws #scalability