https://www.udemy.com/aws-certified-solutions-architect-associate/learn/v4/t/lecture/2050800?start=0

Exam Tips

• RDS
  • Used for OLTP (Online Transaction Processing)
  • SQL Server
  • MySQL
  • PostgreSQL
  • Oracle
  • Aurora
  • MariaDB
• DynamoDB
  • No-SQL
• RedShift
  •  OLAP
  •  Data Warehousing
• ElastiCache
  • In Memory Caching
  • Memcached
  • Redis

What is RDS Multi-AZ

• Used for HA / DR
• Automatically sychronized to alternate AZ when enabled.
• DNS automatically transferred to alternate instance if the primary fails.
  • Can simulate a failover by rebooting the primary instance.

What is RDS Read  Replica

• Used for Read Scaling
• Read Replicas cannot be written to unless promoted to their own DB
  • Doing this breaks all syncronization between it and the original primary DB.
• Can create read replicas of read replicas, but be careful for latency issues.

Aurora

• 2 copies of your data in each AZ, with a minimum of 3 AZs.  This means 6 copies of your data.
  • Can handle the loss of up to 2 copies without affecting write capability.
  • Can handle the loss of up to 3 copies without affecting read capability.
  • Storage is ‘self healing’.  Data blocks and disks are continuously scanned for errors and repaired automatically.
• 2 Types of replics are available.
  • Aurora Replicas (up to 15)
  • MySQL Read Replicas (up to 5)

DynamoDB

• Push button scaling, meaning you can scale your database on the fly without any downtime.
  • You cannot do this with RDS or Aurora. You need to provision a larger instance type or add replicas.
• Stored on SSD storage
• Spread across 3 geographically distinct data centers.
• Read Consistency
  • Eventual Consistent Reads (Default)
  • Strongly Consistent Reads (Guaranteed latency < 1 second)

RedShift

• Single Mode (160Gb)
• Multi-Node
  • Leader Node (manages client connections and receive queries)
  • Compute Nodes (store data and perform queries and computations)
    • Up to 128 compute nodes

ElastiCache

• Caches common queries to reduce load on DB server for data that
  • is frequently accessed
  • does not often change.
• Two supported caching engines
  • Memcached
    • Magento uses this
  • Redis

Quiz Questions

1. Which AWS DB platform is most suitable for OLTP?

( ) ElastiCache
(*) RDS/DynamoDB
( ) RedShift

2) When replicating data from your primary RDS instance to your secondary RDS instance, what is the charge?

( ) Double the standard data transfer charge.
( ) Same as the standard data transfer charge.
(*) No charge, it’s free.
( ) Half the standard data transfer charge

3) What AWS service is best suited for non-relational databases

( ) RDS
( ) RedShift
(*) DynamoDB
( ) ElastiCache

4) When you add a rule to an RDS security group, you do not need to specify a port number o rprotocol.

( ) True
(*) False

5) If you are using RDSProvisioned IOPS storage with MySQL and Oracle database engines, what is the maximum size RDS volume you can have by default?

( ) 500GB
( ) 1TB
( ) 3TB
( ) 5TB
(*) 6TB

6) What happens to the I/O operations while you take a database snapshot

(*) I/O operations are suspended for the duration of the snapshot
( ) Nothing
( ) I/O operations are sent to the Replica (if available) for the duration of the snapshot.
( ) I/O operations will be functioning normally.

7) Which AWS service is best used for Business Intelligence Tools/Data Warehousing?

( ) Elastic Beanstalk
( ) Elasticache
( ) DynamoDB
(*) Redshift

8) In RDS when using multiple availability zones, can you use the secondary database as an independent read node?

(*) No
( ) Only in US-West-1
( ) Depends on how you set it up
( ) Yes

9) Amazon’s ElastiCache uses which two engines?

( ) Redis & Memory
( ) Redis & Memcrush
(*) Redis & Memcached
( ) MyISAM & InnoDB

10) By Default, the maximum provisioned IOPS capacity on an Oracle and MySQL RDS instance (using Provisioned IOPS) is 30,000 IOPS.

(*) True
( ) False