Scalability, Horizontal and Vertical scalability

What is Scalability?

Wikipedia say "Scalability is the ability of a system, network, or process to handle a growing amount of work in a capable manner or its ability to be enlarged to accommodate that growth."

In Database point of View: Scalability is the ability or feature that should be able to support very large databases with very high request rates at very low latency.

In General meaning "scalable database" is the ability of database which can add resources on any way to manage performance easily on growing database or requests.

There are two types of Scalability vertical and horizontal.

Vertical Scalability:

1.)    Increase capacity by adding more resources (memory or additional CPU ) to machine.

2.)    Usually it requires downtime.

3.)    It saves power consumption, less data-center cost and additional cost finance wise.

Horizontal Scalability:

1.)    Horizontal Scalability is the ability to increase capacity by connecting multiple hardware or software entities as a single unit.

2.)    No downtime requires.

3.)    May be costly and sometime unused.

CAP Theoram : Consistency, Availability and Partitioned tolerance / BASE Theory: Basically Available, Soft state, Eventual consistency /ACID : Automatic Consistency Isolation, Duration…

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