Databases

Question 1

RDS DB Tips

Answer 1

SQL server, Oracle, MySQL, Postgre SQL, Mana DB, and Amazon Aurora

Question 2

When to use RDS

Answer 2

Great for online transaction processing, lots of small transactions like customer orders, banking transactions, payments & booking systems

Question 3

When to not use RDS

Answer 3

Not good for online analytics processing.

Use Redshift for data warehousing & OLAP Tasks like analyzing large amounts of data, reporting, and sales forecasting

Question 4

Read Replicas for RDS

Answer 4

1. Scaling Read Performance
   Used for scaling not disaster recovery
2. Requires Automatic Backups
   Automatic backups must be enabled in order to deploy a read replica
3. Multiple Read Replicas are supported
   Maria DB, MYSQL, PostgreSQL, Oracle, & SQL server allow up to 5 read replicas to each instance

Question 5

RDS Multi AZ

Answer 5

An exact copy of your Prod DB in another AZ

Used only for disaster recovery

In the event of a failure RDS will automatically swap to the standby instance

Question 6

What is Amazon Aurora Compatible with?

Answer 6

MySQL and postgreSQL

It is also an Amazon Proprietary db solution

Question 7

Does Amazon Aurora create replicas?

Answer 7

Yes, 2 copies of your data are kept in each AZ w/ a min of 3 AZs = min 6 copies of your data

Supports 3 types of replicas

MySQL

postgre SQL

And Aurora

Only Aurora can do automated failovers from replicas not my sql or Postgre sql

Question 8

Does Aurora support back ups / snapshots?

Answer 8

Yes
Aurora has automated backups turned on by default

You can also take snapshots with Aurora and these are shareable with other AWS accounts

Question 9

Aurora Serverless Use cases

Answer 9

Provides a relatively simple, cost effective option for infrequent, intermittent, or unpredictable workloads

Scenarios about a serverless DB = Aurora

Question 10

General Dynomo DB

Answer 10

Stored on SSD storage

Spread across 3 geographically distinct data centers

Eventually consistent reads

Strongly persistent reads are an option

Question 11

What is Eventually Consistent Read

Answer 11

Consistency across all copies of data is usually reached with in a second.

Repeating a read after a short time should return the updated data.

Best read performance

Question 12

What is a strongly consistent read

Answer 12

A strongly consistent read returns a result that reflects all writes that have received a successful response prior to the read

Question 13

Dynomo DB Transactions

Answer 13

It consists of all or nothing operations

Good for financial transactions

Fulfilling orders

Etc.

Can have up to 25 items or 4 mb of data per write

Question 14

Options for Dynomo DB Transactions

Answer 14

Reads can be: transactional, strong consistency, or eventual consistency

Write can be standard or transactional

Dynomo db transactions provides devs, atomicitu, consistency, isolation and durability (ACID) across one or more tables w/in a single AWS account and region

ACID scenarios think Dynomo DB

Question 15

Dynomo DB on Demand Backup & Restore

Answer 15

Full backups @ anytime

Zero impact on table performance or availability

Consistent w/in same region as the source table

Consistent within seconds & retained until deleted

Question 16

Dynomo DB Point in Time Recovery (PITR)

Answer 16

Protects against accidental write and deletes

Restore to any point in the last 35 days

Incremental back up

Not enabled by default

Latest restorable is 5 min in the past

Question 17

Dynomo DB Streams

Answer 17

Helps maintain first in first out records of your data

Time ordered sequence of item level changes in a table

Stored for 24 hours

Includes: inserts, updates, & deletes

Can combine w/ lambda functions for functionality like stored procedures

Question 18

Dynomo DB Global Tables

Answer 18

Managed multi master multi region replication

For globally distributed apps

Based on streams so streams must be turned on

Multi region redundancy for disaster recovery and availability

No application rewrites

Replication latency under 1 second

To add redundancy you need to turn on global tables and streams