RDS / Dynamo DB Essentials

Question 1

RDS (Acronym definition)

Answer 1

Relational Database Service

Question 2

Describe the difference between RDS and DynamoDB

Answer 2

RDS databases store data in tables using columns and rows, while DynamoDB stores data in JSON-like, name-value documents.

Question 3

T/F - Amazon Aurora offers free tier usage.

Answer 3

False

Question 4

T/F - Amazon RDS databases do not have a GUI in the AWS console.

Answer 4

True

Question 5

What term describes the practice of using SSH to access a resource without a public IP address via a resource with a public IP address (inside of a VPC)

Answer 5

SSH tunneling.

Question 6

Does RDS allow access to the underlying OS?

Answer 6

No - It is a fully-managed service

Question 7

What RDS databases support Read Replicas?

Answer 7

MySQL
PostgreSQL
Aurora

Question 8

How do Relational databases store data

Answer 8

Tables (columns and rows) - associated tables have a defined relationship.

Question 9

Databases supported by RDS

Answer 9

MySQL
MariaDB
PostgreSQL
Oracle
MS SQL Server
Aurora (AWS home grown relational DB)

Question 10

Benefits of RDS

Answer 10

Full managed
Automatic minor updates
Automatic backups
Not required to manage OS
Multi A-Z with a single click
Automatic recovery

Question 11

Are read replicas Synchronous or Asynchronous?

Answer 11

Asynchronous

Question 12

Can you have multiple read replicas of a primary database?

Answer 12

Yes.

Question 13

T/F - Read replicas can be created from other read replicas.

Answer 13

True.

Question 14

How can you monitor replication lag of read replicas?

Answer 14

CloudWatch

Question 15

Benefits of Read Replicas

Answer 15

Allow Read traffic to be redirected from primary db to read replica (increased performance).

Read replicas allow for elasticity - Can add more read replicas as demand increases.

A read replica can be promoted to a primary instance.

MySQL - Replicate for import/export data to RDS. Can replicate across regions.

Question 16

When should you use Read Replicas?

Answer 16

High volume, non-cached database read traffic (elasticity).

Running business function such as data warehousing.

Import/Export data into RDS.

Rebuilding indexes.

Question 17

T/F - AWS provides automated point-in-time backups against the RDS database instance.

Answer 17

True

Question 18

What does MySQL require for reliable backups?

Answer 18

InnoDB

Question 19

What happens to automated backups when the database instance is deleted?

Answer 19

The backups are deleted and cannot be recovered.

Question 20

How can you ensure you have a backup of your database data when the db instance is deleted.

Answer 20

Create your own snapshots / backups before deleting the primary instance.

Question 21

Multi-AZ failover replicates data to a backup database instance located in another AZ zone (same region) using - Asynchronous or Synchronous.

Answer 21

Synchronously

Question 22

When does RDS multi-az failover occur?

Answer 22

1. service outage in an AZ.
2. Primary DB instance failure.
3. Instance server type is changed.
4. Manual failover initiated.
5. Updating software version.
6. AWS will automatically switch the CNAME DNS record from the primary instance to the stand-by instance.

Question 23

What instance are RDS backups taken against?

Answer 23

stand-by instance to reduce I/O freezes and slow down if Multi-AZ is enabled.

Question 24

T/F - In order for Multi AZ to work your primary db instance must be launched into a subnet group.

Answer 24

True.