What is Horizontal scaling in cloud ? What is difference between horizontal and vertical scaling?

Question

What is Horizontal scaling in cloud ? What is difference between horizontal and vertical scaling ?

Answer 1

In very simple terms:

• Horizontal scaling is adding new nodes to increase capacity
• Vertical scaling is using more powerful versions of the current nodes to increase capacity

In the clould world you might meet a given capacity need with either 100 small nodes or 20 very large nodes.

Using lots of small nodes gives you the flexibility to add and remove nodes for small granularity capacity changes as your demand changes. Some would also argue it is more fault tolerant as any one failure has less impact, although you need to look at the solution and in particular any management or clustering technologies in use in a given solution as these can often be sources of failure themselves.

A smaller number of large nodes may be more efficient (less overhead) although performance/efficiency are so solution dependent that you would need to test and measure or else model. Some would argue that a smaller number of nodes may be easier to manage also.