Databases

Question 1

What are the 6 databases available in RDS?

Answer 1

1. PostreSQL
2. MS SQL Server
3. Oracle
4. MariaDB
5. MySQL
6. AWS Aurora (MySQL / PostgreSQL Emulation)

Question 2

What happens in an AWS outage assuming you have a standby database? Is manual intervention required?

Answer 2

• AWS changes the CNAME from primary to backup DB
• Intervention is not needed

Question 3

What is the use case for setting up multi-AZ database? What can you not to against the backup database in another region?

Answer 3

• Failover and/or Disaster recovery (Not to scale the performance)
• You cant run queries against the backup database

Question 4

What are the variations on RDS read replicas?

Answer 4

• Standard
• Multi-AZ

Question 5

Are read replicas Asynchronous or Synchronous

Answer 5

• Asynchronous

Question 6

Can a read replica be promoted to be a primary database? What implications are there?

Answer 6

Yes, but it breaks the replication.

Question 7

What is the main use case for read replicas?

Answer 7

• Scaling (for read heavy loads) not Disaster Recovery

Question 8

What must be enabled to create read replicas?

Answer 8

Automatic backup

Question 9

How many read replicas can you have on an RDS DB

Answer 9

5

Question 10

Which database management systems can Aurora emulate?

Answer 10

• PostreSQL
• MySQL

Question 11

How big is an Aurora DB? By how much does it scale? What is the max size?

Answer 11

• 10GB to start
• Increases automatically in 10GB increments
• Up to 128TB

Question 12

How many vCPUs can Aurora use? How much RAM can it use?

Answer 12

• up to 96vcpus
• up to 768 GB of RAM

Question 13

How many copies of your data are kept when using AWS Aurora

Answer 13

• 2 Per AZ
• Minimum of 3 AZ
• Minimum 6 copies

Question 14

How many copies of data in an aurora database can be lost not affecting performance?

Answer 14

2

Question 15

What types of replicas are available with Aurora? How many Read replicas are available for each?

Answer 15

• Aurora - 15 RRs
• Aurora MySQL - 5 RR
• Aurora PostgreSQL - 5 RR

Question 16

How do aurora backups work?

Answer 16

• Aurora is automatically backed up with no impact to performance.
• Database snapshots can be taken, with no performance impact, these snapshots can be shared with other accounts.

Question 17

Whats the use case for AWS Aurora Serverless?

Answer 17

• Great for spikey or unpredicatable workloads
• Only scales on when needed.
• Scales up and down as needed

Question 18

How is Dynamo DB Stored?

Answer 18

• SSD Storage
• Spread across 3 datacenters (AZs)
• Encrypted at rest

Question 19

What is DAX

Answer 19

• Dynamo DB Accelerator, managed, highly available in-memory cache
• Decreases request time to microseconds
• Developers don’t need to manage it - App speaks directly to DAX
• 10x performance improvement

Question 20

How is Dynamo DB secured?

Answer 20

• Encrypted at rest
• Accessed via policies and roles

Question 21

What are DynamoDB streams?

Answer 21

• Time ordered flow of transactions from DynamoDB
• Has its own endpoint
• up to 24 hours of retention

Question 22

What are use cases for Dynamo DB transactions?

Answer 22

• Financial transactions
• Gaming

Question 23

What about Dynamo DB backup and recovery?

Answer 23

• Can enable backups in the same region. they don’t impact performance.
• Point in time recovery is available but must be enabled.

Question 24

What is a use case for using Dynamo DB Global Tables?

What technology in DynamoDB is required to use this?

Answer 24

• Replicating data from one table to another in real-time
• Globally distributed applications
• Global Tables is based on DynamoDB streams.

Question 25

If you have a multi-AZ backup of your RDS DB 1. Where are backups taken from? 2. Are updates and maintenance updates applied to the backup DB?

Answer 25

1. Backups are taken from the secondary DB 2. Maintenance patches are applied to the backup

Question 26

Are RDS Multi AZ Deployments Synchronous or Asynchronous?

Answer 26

Synchronous

Question 27

How much will DynamoDB scale?

Answer 27

* up to 10 trillion requests per day * up to 20 million requests per second * Petabytes of storage

Question 28

What is an Aurora Endpoint used for?

Answer 28

Aurora exists in a cluster, each of which has an endpoint. you connect to the cluster. the endpoint abstracts this. Using endpoints, you can map each connection to the appropriate instance or group of instances based on your use case.

Question 29

Which AWS DB solutions allow you to store web application state data (key, value)

Answer 29

* Elasticache (Redis) * DynamoDB

Question 30

What would you use for a global RDS solution with aggressive recovery?

Answer 30

Aurora Global Database

Question 31

How would you capture data changes in Aurora when a row is deleted?

Answer 31

Invoke a Lambda function from aurora with a native function or stored procedure.

Question 32

How would you configure a connection from EC2 to an RDS DB using an authentication token? which DBs does this apply to?

Answer 32

User IAM DB Authentication IAM database authentication works with MariaDB, MySQL and PostgreSQL