Databases Flashcards
What is Aurora?
Amazon’s RDS service
5x faster than MySQL
Easy migration from MySQL
Default 6 copies across multi AZs
On the exam, when given a question about what the most scalable and highest performance RDS offering is, what should you choose?
Aurora
What are the two key features of RDS Services in AWS?
Multi-AZ - disaster recovery
Read Replicas - Performance
How do Read Replicas work?
Exact Copies of DB
Different AZs
No failover
Caching for read intensive loads
How does the multi-AZ feature work in AWS RDS?
Primary DB goes down in AZ1
DNS points traffic to the replica in AZ2
With AWS RDS, how does an EC2 instance connect to the DB instance / Replica and why?
Using a DNS address
Amazon handles the DNS changes for you
Can multi-AZ and Read Replicas be used together?
Yes. If a failover occurs, the DB in the second AZ will start to sync to the Read Replicas
Given a news site how would you arrange an infrastructure with one EC2 instance, a primary RDS and 5 read replicas?
EC2 connects to DNS
Read traffic gets spreas evenly over 5 replicas
writes go directly to the primary DB
How many read replicas can exist for one DB?
Max 5
What are the conceptual components of a non relational DB and what are they analogous to in the RDS world?
Collection = Table
Document (JSON) = Row
Key Value Pairs (Objects) = Fields
What are the characteristics of DynamoDB
NoSQL
AWS Service
Single Digit millisecond latency at any scale
Given an exam question about the need for automatic scaling but no indication of a relational or non-relational DB, what do you choose?
DynamoDB
For exam questions about business intelligence or data warehousing, what should you choose?
Redshift
