ElastiCache

Question 1

What are the available cache stores in RDS?

Answer 1

Managed Redis or Memcached

Question 2

What are some of the uses of elasticache?

Answer 2

User session store

Helps reduce load off of database for read intensive workloads

Question 3

What are some of the features of Redis for HA and scaling?

Does Redis support backup and restore?

How does Redis support Data durability?

What is a Redis sorted set?

Answer 3

Multi AZ with Auto-failover
Read Replicas to scale reads and have high availability

Yes

Data Durability using append only file (AOF) persistence

A prioritized list feature called Redis Sorted Sets. That can be used to store/retrieve leaderboard type information

Question 4

What is memcached?

Does Memcached support HA (Replication), persistence or backup and restore?

What is memcached multi-node support?

Answer 4

Network attached in memory cache

No

Supports multithreading

Multi-node for partitioning of data. A node is a fixed-size chunk of secure, network-attached RAM.
A Memcached cluster can have from 1 to 40 nodes.
Memcached clusters scale horizontally easily by adding or removing nodes.

Question 5

Is there IAM authentication in ElastiCache?

Answer 5

They do not support IAM authentication.

Question 6

What are the IAM policies used for in ElastiCache?

Answer 6

IAM policies on ElastiCache are only used for AWS API level security

Question 7

What are some of the security features of Redis?

Answer 7

Can set password/token when you create a redis cluster
This is an extra layer of security on top of security groups

Supports SSL

Question 8

What are some of the security features of Memcached?

Answer 8

Supports SASL-based auth.

Question 9

What are the 3 caching patterns?

Answer 9

Lazy loading - All the read data is cached and can become stale in cache

Write through - adds or update data in the cache when written to DB (No stale data)

Session store - Store temporary session data in a cache using TTL