Module 6 - Database Services

Question 1

What relational databases does AWS offer?

Answer 1

Amazon RDS
Amazon RedShift
Aurora

Question 2

What NoSQL databases does AWS offer?

Answer 2

DynamoDB

ElastiCache

Question 3

What do I need to consider when deciding on a database product?

Answer 3

• Read and write needs
• Total storage requirements
• Typical object size and nature of access to these objects
• Durability requirements
• Latency requirements
• Maximum concurrent users to support
• Nature of queries
• Required strength of integrity controls

Question 4

How do you get high availability for database workloads?

Answer 4

Use Multi-AZ deployments with RDS. It auto replicates in another AZ; in case of failure, it switches over to the backup. Then the backup becomes primary and the newly spun up db becomes the backup.

Question 5

How should I handle read-heavy workloads?

Answer 5

RDS with a Read Replicas. The primary DB is read/write, replicas are read-only. Replicas can be promoted to primary read/write in case of failure.

Question 6

How does RDS manage encryption at rest?

Answer 6

AWS KMS.

Question 7

What is Aurora?

Answer 7

A relational database compatible with MySQL and PostgreSQL, but faster. Built for cloud. Managed by RDS so no maintenance.

Stored across 3 AZs with 2 backup copies for each instance, with up to 15 replicas per cluster.

Question 8

What database should I use if I need high availability?

Answer 8

Aurora.

Question 9

What if my database needs are highly variable?

Answer 9

Use Aurora Serverless. Auto scales on-demand from a pool of prewarmed instances.

Question 10

I need a NoSQL database but I don’t want to deal with managing the cluster.

Answer 10

DynamoDB. Handles all the architecture decisions, optionally auto-scales.

Question 11

What are 2 ways to auto-scale?

Answer 11

Provisioned - set a min and max, looks like steps

On-Demand - for spiky workloads

Question 12

What are the consistency options for DynamoDB?

Answer 12

Strongly consistent
Eventually consistent (default)

Question 13

What is an AWS option for a data warehouse?

Answer 13

Amazon RedShift. Fully managed, cloud-native.

Question 14

What are some use cases for RedShift?

Answer 14

• Business intelligence: run high-performance queries on petabytes of semi-structured and structured data
• Operational analytics on events: Bring together structured data from your data warehouse and semi-structured data such as application logs from your S3 data lake to get real-time operational insights on your applications and systems.
• Data as a service: Share data inside and outside your organization for secure and governed collaboration on live data with Amazon Redshift data sharing.
• Predictive analytics: Use SQL to automatically create, train, and deploy Amazon SageMaker models on the data in your data warehouse with Amazon Redshift Machine Learning (preview)

Question 15

How does RedShift organize data?

Answer 15

By column; ideal for warehousing and analytics, large data sets.

Question 16

What if I need to auto-scale RedShift?

Answer 16

Turn on concurrency scaling.

Question 17

What are the node types for RedShift?

Answer 17

3rd generation (RA3) - optimize your data warehouse by scaling and paying for compute and managed storage independently.

Dense compute nodes (DC2) - compute-intensive data warehouses with local SSD storage included.

Question 18

What are 2 caching strategies for a database?

Answer 18

Lazy-loading - update cache only on a miss

Write-through - update cache on every write

Question 19

What is ElastiCache?

Answer 19

A service for in-memory data store or cache environment in the cloud. Support Redis, Memcached. Creates a caching tier for data-intensive apps. Works as an in-memory data store.

Question 20

What is TTL?

Answer 20

An integer value that specifies the number of seconds or milliseconds until the key expires. When the key expires the cache goes back to the database to get fresh data.

Question 21

What can you use to increase response times on DynamoDB?

Answer 21

DynamoDB Accelerator(DAX). It’s a caching in memory service.

Question 22

How can you migrate an on-prem database to the cloud?

Answer 22

AWS DMS. Database Migration Service. For Oracle, PostgreSQL, SQL Server, Amazon Redshift, Aurora, MariaDB, and MySQL.

automatically handles formatting of the source data for consumption by the target database

Question 23

What if I am migrating to a different engine?

Answer 23

For heterogeneous migrations, you can use the AWS Schema Conversion Tool (AWS SCT).

Automatically converts the source database schema and code objects. The conversion includes views, stored procedures, and functions.

Question 24

What is the benefit of using RDS in a multi-AZ configuration?

Answer 24

Automatic failover across AZs.

Question 25

What type of ElastiCache installation offers sorting and ranking for data sets?

Answer 25

ElastiCache for Redis.

Question 26

What are DynamoDB global tables?

Answer 26

Multiple replica tables (one per AWS Region) that DynamoDB treats as a single unit. Tables can be in different regions.

Question 27

I need to give engineers access to ElastiCache for Redis sessions. How do you secure the session requiring a password before they can execute Redis commands?

Answer 27

Authenticate the users using Redis AUTH (make a new Redis cluster and enable auth token and transit encryption).

Using Redis AUTH improves data security by requiring users to enter a password before executing Redis commands.