Learn to work with the most fundamental services AWS offers such as DynamoDB, S3, and EC2 to create reliable and scalable systems.

Scalability & System Design for Developers

In this module, we’ll learn to work with the most fundamental services AWS offers, such as DynamoDB, S3, and EC2 to create reliable and scalable systems. Walk through getting a basic web application running in the cloud on AWS. You won’t find most of the knowledge that's shared here in the AWS docs.

The Good Parts of AWS: Cutting Through the Clutter

## Optimization fallacy

Chasing the best tool for the job is a particularly insidious
trap when it comes to making progress—especially at the
beginning of a project. We consider the relentless search
for the best tool to be an **optimization fallacy**—in the
same category as any other premature optimization.


Searching for the optimal option is:
- Almost always expensive. 
- Any belief that we can easily discover the best
option by exhaustively testing each one is delusional. 

To
make matters worse:
- We developers tend to enjoy
tinkering with new technology and figuring out how
things work, and this only amplifies the vicious cycle of
such a pursuit.

## The default heuristic 

Instead of searching for the best option, we recommend a technique we call the default heuristic. The premise of
this heuristic is that when the cost of acquiring new
information is high and the consequence of deviating
from a default choice is low, sticking with the default will likely be the optimal choice.


But what should your default choice be?

- It should be any option that gives you very high confidence that it
will work. 
- It is something you’ve used before. 
- Something you understand well. 
- Something that has proven itself to be a reliable way for getting things
done in the space you’re operating in.
- It doesn’t necessarily have to be the theoretical best choice. 
- It doesn’t have to be the most efficient. Or the latest and greatest. 
- It simply needs
to be a reliable option to get you to your ultimate desirable outcome. 
- It should be very
unlikely to fail you; you have to be confident that it’s a
very safe bet. In fact, that’s the only requirement.


With this heuristic, you start making all your choices
based on your defaults. You would only deviate from your
defaults if you realize you absolutely have to.


Let's take a small quiz to check your understanding of the default heuristic. 


# Optimization fallacy

Chasing the best tool for the job is a particularly insidious
trap when it comes to making progress—especially at the
beginning of a project. We consider the relentless search
for the best tool to be an **optimization fallacy**—in the
same category as any other premature optimization.


Searching for the optimal option is:
- Almost always expensive. 
- Any belief that we can easily discover the best
option by exhaustively testing each one is delusional. 

To
make matters worse:
- We developers tend to enjoy
tinkering with new technology and figuring out how
things work, and this only amplifies the vicious cycle of
such a pursuit.

# The default heuristic 

Instead of searching for the best option, we recommend a technique we call the default heuristic. The premise of
this heuristic is that when the cost of acquiring new
information is high and the consequence of deviating
from a default choice is low, sticking with the default will likely be the optimal choice.


But what should your default choice be?

- It should be any option that gives you very high confidence that it
will work. 
- It is something you’ve used before. 
- Something you understand well. 
- Something that has proven itself to be a reliable way for getting things
done in the space you’re operating in.
- It doesn’t necessarily have to be the theoretical best choice. 
- It doesn’t have to be the most efficient. Or the latest and greatest. 
- It simply needs
to be a reliable option to get you to your ultimate desirable outcome. 
- It should be very
unlikely to fail you; you have to be confident that it’s a
very safe bet. In fact, that’s the only requirement.


With this heuristic, you start making all your choices
based on your defaults. You would only deviate from your
defaults if you realize you absolutely have to.


Let's take a small quiz to check your understanding of the default heuristic. 


The Default Heuristic technique helps solve our struggle for searching the best AWS services and features.

Part 1: The Good Parts

Part 2: The Bootstrap Guide

The Default Heuristic

Optimization fallacy