Caching

Question 1

Why do we use caches?

Answer 1

To place content closer to end users

Question 2

What 2 places do you place caches?

Answer 2

1. External - to end users like images, videos, static content
2. Internal - in front of a database for reads

Question 3

What is Cloudfront?

Answer 3

Content delivery network for external caching for placing resources globally using AWS Edge Location

Question 4

What are 4 caching services?

Answer 4

1. CloudFront
2. ElastiCache
3. DAX
4. Global Accelerator

Question 5

Why use CloudFront? 4 things

Answer 5

1. Enables default HTTPS for your content
2. Secure connection for S3 static websites
3. Can be used for non-AWS (on-prem) applications
4. Can force an expiration on cached content

Question 6

What is a major restrictions on CloudFront?

Answer 6

1. You can’t really block specific countries, you should use WAF instead, as restriction is by general geographies
2. You can’t pick specific Edge Locations for caching, its either all locations or specific geographies

Question 7

Can you use Presigned URLS or Cookies?

Answer 7

Yes you can give temporary access content using presigned urls/cookies with CloudFront

Question 8

What are the 2 SSL options with CloudFront?

Answer 8

You can use a default ssl certificate or give a custom ssl certificate with your own domain name to be used with CloudFront

Question 9

What is ElastiCache?

Answer 9

AWS Managed caching service using Redis or Memcached

Question 10

Can Redis be used as a database?

Answer 10

Yes Redis can be a standalone NOSQL database as well as a caching solution

Question 11

What are the 4 difference between Redis and Memcached?

Answer 11

1. Redis provides more complex caching solution vs simpler caching
2. Redis can be standalone db vs. just a caching solution
3. Redis has failover and MultiAZ vs none of these
4. Redis has backups vs no backups

Question 12

What is DAX?

Answer 12

DynamoDB Accelerator, in memory caching for milliseconds down to microseconds

Question 13

What location is DAX located?

Answer 13

1. Lives in a VPC you choose

Question 14

What are 2 benefits of DAX other than the reduced latency?

Answer 14

1. It is HA

2. Has lots of configurations for you

Question 15

WHat is GLobal Accelerator?

Answer 15

Uses AWS global network (Edge locations) to help increase performance

Question 16

How do you solve the issues of IP Caching by end users?

Answer 16

You can uses Global Accelerator

Question 17

How does GLobal Accelerator solve IP Caching?

Answer 17

It gives 2 static ips to end users, and Global Accelerator sits between end users and the ELB

Question 18

What are 3 benefits of Global Accelerator?

Answer 18

1. Gives 2 static ip’s that mask any architecture changes behind
2. Speeds up network traffic due to Edge Locations AWS backbone
3. Weighted pools with different endpoints to provide failover or A/B testing

Question 19

Do you have to use the 2 static IP’s from AWs? for Global Accelerator

Answer 19

No, you can bring your own custom ip’s

Question 20

IF you see in memory databse on exam what should you pick? favor which of them?

Answer 20

1. Redis and DyanmoDB

2. Favor DynamoDB

Question 21

Does DAX have backups?

Answer 21

No it does not, it is not a database solution