Databases

Question 1

What is ElasticCache?

Answer 1

an in memory cache in the cloud. * Allows you retrieve data a lot quicker, by pulling data from memory cache in the cloud rather than slower disk-based databases. supports master and slave replication.

Question 2

What are the two types of Elacticcache ?

Answer 2

Memcached Redis (opensource in-memory key-value store)

Question 3

AWS Database types?

Answer 3

RDS-OLTP DynamoDB (No SQL) RedSHift (Amazon’s OLAP data warehouse product) Elasticache

Question 4

AWS Database RDS OLTP examples:

Answer 4

SQL MySQL PostgreSQL Oracle Aurora (AWS MySQL & PostgreSQL compatible DB) MariaDB

Question 5

RDS Backups.

Answer 5

There are two: 1) Automated backups 2) Database snapshots

Question 6

RDS Backup - Automated backup - key points:

Answer 6

1) Retention 1 - and 35 days. 2) Backup is a fully daily snapshot 3) Stores transactional logs 4) Recovery will first choose the most recent daily backup then apply transaction logs for that day. 5) enabled by default

Question 7

RDS Backup - database snapshots - key points:

Answer 7

1) Always manual. (User initiated) 2) Are restored even after you delete the original RDS instance. A restored RDS instance will be a new RDS instance with a new DNS endpoint.

Question 8

Database Encryption:

Answer 8

Encryption at Rest: * MySQL, Oracle, SQ Server, PostgreSQL, MariaDB and Aurora. * Encryption is done using the AWS key management service. * backups, replicas and snapshots are encrypted.

Question 9

Database and Multi AZ :

Answer 9

Designed for DR recovery. Writes to 1 Database is replicated to database 2. * Failover is automated. * not a performance improvement. Available: SQL Server, Oracle, MySQL, PostgreSQL, MariaDB, Aurora.

Question 10

Databases and Read Replicas:

Answer 10

This is designed to increase Database performance by reading out, but not for redundancy. you have a read replica of a read replica (some latency) you have 5 read replicas per production database. This is asynchronous. Read replicas can have multi-AZ enabled. Read Replicas can be promoted to their own DB. Must have automatic backups turned on in order to deploy a read-replica. Can enable encryption even if the primary database is not encrypted.

Question 11

What is DynamoDB ?

Answer 11

It is a fast and flexible NoSQL Database service. It provides: consistent, single digit millisecond latency at scale. Great fit for: mobile, web, gaming, ad-tech, IoT.

Question 12

DynamoDB Data points:

Answer 12

1) Stored on SSD. 2) Spread across 3 geographically distinct data centres. 3) Eventual consistent reads. (best read performance) 4) Strongly consistent reads. (best write performance)

Question 13

DynamoDB Pricing ?

Answer 13

Provisioned through capacity. * Write throughput. * read throughput * storage costs.

Question 14

What is RedShift ?

Answer 14

RedShift is Amazon’s dataware house service in the cloud. (petabyte scale)

Question 15

Red Shift Costs ?

Answer 15

1) Compute node hours 2) backup 3) data transfer within a VPC.

Question 16

What is OLAP ?

Answer 16

Online Analytics Processing

Question 17

Redshift Config :

Answer 17

Single Node or Multi node config. In a multi node setup there is a leader node and compute nodes. (max 128 compute nodes)

Question 18

RedShift Node Info:

Answer 18

Single Node (160Gb)

Question 19

RedShift data points:

Answer 19

1) columnar data storage: data is stored in columns not rows. (fewer I/O, improved performance on queries). 2) Adv. compression. 3) Massively parallel processing (MPP) It scales fast and easily))

Question 20

RedShift Security:

Answer 20

1) Data in transit uses SSL 2) Data at rest uses AES-256 3) RedShift takes care of key management (you can manage your own however)

Question 21

RedShift Availability:

Answer 21

Only available in 1 AZ. Can restore snapshots to new AZs in the event of an outage.

Question 22

What is Aurora?

Answer 22

A bespoke database created by AWS. It is compatible with MySQL and PostgreSQL.

Question 23

Aurora Data Points:

Answer 23

1) 5x better performance than MySQL 2) 1/10th of the cost of MySQL.

Question 24

Aurora Scaling:

Answer 24

Storage: starts with 10GB, then auto scales at 10GB increments. Compute: scale up to 32vCPUS & 244GB Ram Availability: 2x copies of your data per availability zone, with 3 availability zones. (Can handle the loss of up to 2 copies of data with affecting DB write availability, and can handle the loss of 3 copies of data before affecting DB read availability).

Question 25

Aurora Replicas:

Answer 25

2 types of replicas are available. it supports up to 15 replicas. it allows for MySQL read replicas (up to 5 replicas) replicas can be multi AZ.

Question 26

List all Amazon Database Services

Answer 26

• Amazon RDS
• Amazon Aurora
• Amazon RedShift
• Amazon DynamoDB
• Amazon DocomentDB
• Amazon ElastiCache for Memcached
• Amazon ElastiCache for Redis
• AWS DB Migration service

Question 27

What is RDS ?

Answer 27

Cost-efficient and resizable manages time consuming DBs Fast to deploy isolated DB environment in the cloud Example: MySql, PostgreSQL, MS SQL, MariaDB, Oracle, Amazon Aurora.

Question 28

What is Amazon DynamoDB ?

Answer 28

Similar to MongoDB / Cassandra NoSQL. No limit on storage fully managed. need to spec the Read and Write throughput.