Section - RDS Databases

Question 1

What is Amazon Relational Database Service (RDS)?

Answer 1

RDS is a service that makes it easy to launch and manage relational databases.

• Supports popular database engines
• Offers high availability and fault tolerance using Multi-AZ deployment option
• AWS manages the database with automatic software patching, automated backups, operating system maintenance, and more.
• Amazon RDS Read Replicas provide enhanced performance and durability for RDS database (DB) instances. They make it easy to elastically scale out beyond the capacity constraints of a single DB instance for read-heavy database workloads.

Question 2

AWS Supported Relational Database Engines?

Answer 2

• Microsoft SQL Server
• Oracle
• MySQL
• PostgreSQL
• MariaDB
• Amazon Aurora

Question 3

When would we use an RDS database?

Answer 3

• RDS is generally used for Online Transaction Processing (OLTP) workloads.

Question 4

Difference bwteen OLTP and OLAP?

Answer 4

Online Transaction Processing(OLTP):

• Processes data from transactions in real-time e.g. customer orders, banking transactions, payments and booking systems.
• OLTP is all about data processing, and completing large numbers of small transactions in real-time.

Online Analytics Processing (OLAP):

• Processes complex queries to analyze historical data, e.g. analyzing net profit figures from the past 3 years and sales forecasting.
• OLAP is all about data analysis using large amounts of data and complex queries that take a long time to complete.

Question 5

List 6 different types of databases supported by the AWS ecosystem?

Answer 5

• RDS
• Aurora
• DynamoDB
• DocumentDB
• ElastiCache
• Neptune

Question 6

What is Multi-AZ?

Answer 6

• It’s an exact copy of your production database in another Availability Zone.
• AWS handles the replication for you.
• Multi-AZ is used for Data recovery
• Multi-AZ not for improving performance.
• In the event of a failure, RDS will automatically fail over to the standby instance.
• You cannot connect to the Standby when the Primary DB is active.
• Which databases can be configured as Multi-AZ:
  
  • SQL Server
  • Oracle
  • MySQL
  • PostgreSQL
  • MariaDB

Question 7

What is a Read Replica?

Answer 7

• A Read Replica is a read-only copy of the primary database.
• A Read Replica can be located at the same availability zone
• A Read Replica can be Cross-AZ, located in a different availability zone.
• A Read Replica can be cross region, located in a different region.
• Each read replica has it’s own DNS endpoint.
• A Read Replica can be promoted to be their own databases. This however breaks the replication.
• Read Replica is used for scaling read perfomance, not for DR
• Requires automatic backup: Automatic backups must be enabled in order to deploy a read replica.
• Multiple Read Replicas are supported; MySQL, Oracle, MariaDB,PostgreSQL and SQL server allow you to add up to 5 read replicas to each DB instance.

Question 8

What are the two types of Backups supported by RDS?

Answer 8

• Database Snapshot:
  
  • Manual,ad-hoc and user-initiated.
  • It provides a snapshot of the storage volume attached to the DB instance
• Automated Backup:
  
  • Enabled by default
  • It creates daily backups or snapshots that run during a backup window that you define.

Question 9

RDS Encryption at Rest?

Answer 9

• Enable encryption at creation time by selecting the encryption option in the console.
• Encyrption is done using AWS Key Management Service (KMS) AES-256 encryption
• Encryption is applied to all underlying storage, auotmated backups,snapshots,logs, and read replicas.
• Encryption cannot be applied to an unencrypted RDS DB instance. (Must be done at creation)
• Creating an encrypted database from an unencrypted RDS instance
  
  • Take a snapshot (uncrypted)
  • Encrypt snapshot
  • Restore DB from encrypted snapshot

Question 10

RDS Automated Backups Features?

Answer 10

• Point-In-Time Recovery
  
  • Recover your database to any point in time within a “retention period” of 1-35 days.
• Full daily Backup
  
  • RDS takes a full daily backup, or snapshot, and also stores transactions logs throughout the day.
• The recovery Process
  
  • When you do a recovery, AWS will first choose the most recent daily backup and then apply transaction logs relevant to that day, up to the recovery point.
• Stored in S3
  
  • Automated backups and snapshots are stored in s3
• Free Storage
  
  • You get free storage space equal to the size of your database. So if you have an RDS instance of 10GB, you will get 10GB orth of storage.

Question 11

The 3 types of Aurora Replicas Available?

Answer 11

• Aurora Replicas
  
  • You can currently have 15 read replicas with Aurora
• MySQL Replicas
  
  • You can currently have 5 read replicas with Aurora MySQL
• PostgreSQL
  
  • You can currently have 5 read replicas with Aurora PostgreSQL

Question 12

What is Amazon Aurora?

Answer 12

Aurora is a relational database compatible with MySQL and PostgreSQL that was created by AWS.

• Supports MySQL and PostgreSQL database engines
• 5x faster than normal MySQL and 3x faster than normal PostgreSQL
• Scales automatically while providing durability and high availability
• Managed by RDS
• Start with 10 GB, scales in 10-GB increments to 128 TB (Storage Auto Scaling)
• Compute resources can sclae upto 96 vCPUs and 768 GB of memory.
• 2 copies of your data are contained in each Availabilty Zone; with a minimum of 3 Availability Zone. 6 copies of your data.
• Aurora is designed to transparently handle the loss of up to 2 copies of data without affecting database write avilability and up to 3 copies without affecting read availability.
• Aurora storage is also self-healing. Data blocks and disk are continously scanned for errors and repaired automatically.

Question 13

Aurora Backups?

Answer 13

• Automated backups are always enabled on the Amazon Aurora DB instances. Backups do not impact database performance.
• You can also take snapshots with Aurora. This also does not impact on performance.
• You can share Aurora snapshots with other AWS accounts.

Question 14

Amazon Aurora Serverless?

Answer 14

• An on-demand; auto-sclaing configuration for MySQL-compatible and PostgreSQL-compatible editions of Amazon Aurora.
• An Aurora Serverless DB Cluster automatically starts up; shuts down; scales capacity up or down based on your application’s needs.

Question 15

Amazon Aurora Serverless Use Cases?

Answer 15

Aurora Serverless provides a relatively simple, cost-effective option for infrequent, intermittent, or unpredictable workloads.