Domain 3: Technology - Databases Flashcards

1
Q

What is Aurora?

A

Amazon’s RDS service

5x faster than MySQL

Easy migration from MySQL

Default 6 copies across multi AZs

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2
Q

On the exam, when given a question about
what the most scalable
and highest performance
RDS offering is, what should you choose?

A

Aurora

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3
Q

What are the two key features of RDS Services in AWS?

A

Multi-AZ - disaster recovery

Read Replicas - Performance

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4
Q

How do Read Replicas work?

A

Exact Copies of DB

Different AZs

No failover

Caching for read intensive loads

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5
Q

How does the multi-AZ feature work in AWS RDS?

A

Primary DB goes down in AZ1

DNS points traffic to the replica in AZ2

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6
Q

With AWS RDS, how does an EC2 instance connect to the DB instance / Replica and why?

A

Using a DNS address

Amazon handles the DNS changes for you

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7
Q

Can multi-AZ and Read Replicas be used together?

A

Yes. If a failover occurs, the DB in the second AZ will start to sync to the Read Replicas

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8
Q
Given a news site,
how would you arrange an infrastructure with 
one EC2 instance, 
a primary RDS
and 5 read replicas?
A

EC2 connects to DNS

Read traffic gets spread evenly over 5 replicas

writes go directly to the primary DB

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9
Q

How many read replicas can exist for one DB?

A

Amazon RDS allows you to add up to 5 read replicas to each DB Instance.

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10
Q

What are the conceptual components of a non relational DB and what are they analogous to in the RDS world?

A

Collection = Table

Document (JSON) = Row

Key Value Pairs (Objects) = Fields

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11
Q

What are the characteristics of DynamoDB

A

NoSQL

AWS Service

Single Digit millisecond latency at any scale

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12
Q

Given an exam question about the need for automatic scaling but no indication of a relational or non-relational DB, what do you choose?

A

DynamoDB

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13
Q

For exam questions about business intelligence or data warehousing, what should you choose?

A

Redshift

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