Services - Database

Question 1

Aurora - Characteristics 1

Answer 1

• It’s a managed MySQL and PostgreSQL compatible relational database built for the cloud
• AWS is responsible for software patching, configuration, and backups
• Backups are automatically stored in S3
• Aurora serverless is an on-demand, auto-scaling configuration for Aurora

Question 2

Aurora - Characteristics 2

Answer 2

• Can scale up / down database deployment to smaller / larger instance types. Or use Aurora serverless to scale automatically
• Maintains six copies of data across 3 AZs and can automatically attempt to recover the database in an AZ
• Can create up to 15 read replicas and automatically grows as needed up to 128GB per database instance
• An Aurora Replica is both a standby in a Multi-AZ deployment, and a target for read traffic
• To create a database must go to RDS service, and then select Aurora

Question 3

Aurora - Pricing components

Answer 3

• Instance hosting: varies by instance type
• Storage, I/O consumed, and user backups. There’s no additional charge for the built‑in backups
• Data transferred out to the internet and to other AWS regions
• On Aurora serverless you pay for the database capacity, storage, and I/O consumed when it’s active

Question 4

Aurora - Instance types pricing

Answer 4

• On-demand instance: pay for compute by the hour
• Reserved instance: secure a 1 or 3 year contract in exchange for discounts over on-demand

Question 5

ElastiCache - Definition and pricing

Answer 5

• It’s a managed service that helps to deploy, operate, and scale an in‑memory cache / database in the cloud
• Pay only for what you use, more than one storage snapshot, and data transferred in / out of an EC2 instance

Question 6

ElastiCache - Open source Cache engines supported

Answer 6

• Redis: supports complex data types, data replication, and high availability. It’s ideal for session caching, full‑page caching, message queue applications, leaderboards, and others
• Memcached: it’s for data that is relatively small and static. It’s multi-threaded and allows data partitioning

Question 7

ElastiCache - Node types

Answer 7

• On-demand: pay for the memory capacity by the hour
• Reserved: commit to 1 or 3 year term to save up to 75% over on-demand rates