Scalability & High Availability

Question 1

What does Scalability means?

Answer 1

Means that an application / system can handle greater loads by adapting

Question 2

What are the 2 kinds of Scalability?

Answer 2

Vertical and Horizontal (elasticity)

Question 3

What vertically scalability means?

Answer 3

increasing the size of the instance (there is usually a limit to how much you can vertically scale)

Question 4

What horizontal scalability means?

Answer 4

increasing the number of instances / systems for your

application

Question 5

What does High Availability means?

Answer 5

means running your application / system in at least 2 data centers (== AZ)

Question 6

What does mean

• scale up
• scale down
• scale out
• scale in

Answer 6

scale up = increase size
scale down = decrease size
scale out = increase number
scale in = decrease number

Question 7

What is Vertical scalability very common for?

Answer 7

non-distributed systems, such as a database (RDS, ElastiCache)

Question 8

Is there a limit to how much you can vertically scale?

Answer 8

Yes, there is a hardware limit

Question 9

What is Horizontal scaling very common for?

Answer 9

For distributed systems, such as web applications / modern applications.