Section 9: AWS Fundamentals: RDS + Aurora + ElastiCache

Question 1

What can you do with Aurora Custom Endpoints?

Answer 1

Define a subset of Aurora instances as a Custom endpoint
Could have a Analytical queries on specific replicas

Question 2

What is ElastiCache?

Answer 2

ElastiCache is to get managed Redis or Memcached

Question 3

What’s the difference between Redis and Memcached?

Answer 3

Redis
• Multi AZ - auto fail over
• Read Replicas - reads have high availability
• Data Durability using AOF persistence
• Back up and restore features

Memcached
• Multi-node for partitioning of data
• No high availability
• Non persistant
• no back up and restore
• multi threaded architecture

Question 4

How can you authenticate Redis?

Answer 4

• Can set a password/token when creating the Redis cluster (on top of security groups)
• Supports SSL in flight encryption

Question 5

Does Elasticache support IAM authentication?

Answer 5

NO

Question 6

What kind of security does Memcached support?

Answer 6

SASL-based auth

Question 7

What are 3 patterns for ElastiCache?

Answer 7

Lazy Loading: All the read data is cached, data can become stale in cache.

Write through: Adds or update data in cache when written to DB (no stale)

Session store: Stores temporary session data in cache (TTL features)

Question 8

What is Global Aurora and is that use case?

Answer 8

Aurora that spans multiple AWS regions. (Cross region read replicas)

Disaster recovery

Question 9

List the characteristics of Aurora Global Database

Answer 9

• 1 primary region (R/W)
• 5 secondary regions - replication lag is < 1 sec
• 16 read replicas per secondary region
• helps decrease latency
• promoting to another regions has an RTO of < 1 min
• Cross region replication < 1 sec