Chp 9: AWS Fundamentals- RDS, Aurora, & Elasticache Flashcards
What is Amazon Aurora
Amazon Aurora is a MySQL and PostgreSQL-compatible relational database built for the cloud that combines the performance and availability of traditional enterprise databases with the simplicity and cost-effectiveness of open source databases.
Advantages of Amazon Aurora
- An AWS managed service
- automated updates
- automated backups
RDS- Autoscaling group
Helps increase storage on your RDS DB instance dynamically. It scales automatically when it detects resources are running out.
When is using RDS (ASG) useful?
useful for apps with an unpredictable workload
Who sets the RDS max storage threshold
user have to manually set it
How many read replicas for RDS?
5 read replicas
Can read replicas scale within regions? wherelse?
regions, across AZ, and across region
T/F RDS read replicas cannot be promoted to its own database
FALSE… It CAN be promoted
How do apps leverage read replicas?
They have to update the connection string
RDS read replicas are used for what kind of statements?
READ statements
RDS Read replicas – is there a cost when data goes from one AZ to another?
yes there is
When are RDS read replicas free?
when they are within the same region
How to set up RDS read replicas for disaster recovery?
Read replicas are set up as multi AZ
is RDS multi AZ used for scaling and availability?
its used to increase availability and not used for scaling
Ecryption tupes for RDS read replicas
- at rest encryption
2. in flight encryption
Describe at rest encryption
- encrypt using aes-256
- encryption has to be defined at launch time
- if the master is not encrypted, then the read replicas cannot be encrypted
Describe in flight encryption
- SSL certs
T/F: A user can copy a snapshot of an unencrypted db can turn into a encrypted one
tru
what subnet is used when deploying a RDS database?
RDS db are usually deployed within a private subnet
describe RDS security
security works by leveraging security groups. it controls which ip/sg can communicate with RDS
describe access management for RDS
- IAM policies control who can manage RDS
- traditional UN & PW can be used to login into db
- IAM-based authentication can be used to login into RDS MySQL + Postgres
are mysql and postgres supported as Aurora DB>
yes
Aurora High Availability + Read Scaling
- 6 copies of your data across 3 AZ
- 1 is a master /writes
- support for cross region replication
When is aurora cross region read replicas useful?
useful for disaster recovery
describe aurora global db
- 1 primary region with r/w
- 5 secondary read only
- up to 16 read replicas per secondary region
- helps for decreasing latency
What is ElastiCache?
Amazon ElastiCache is a fully managed, in-memory caching service supporting flexible, real-time use cases. You can use ElastiCache for caching, which accelerates application and database performance, or as a primary data store for use cases that don’t require durability like session stores, gaming leaderboards, streaming, and analytics. ElastiCache is compatible with Redis and Memcached.
Describe ElastiCache Redis
- multi AZ with auto-failover
- read replicas to scale reads and have high availability
- data durability using persistence
- backup + restore features
Describe ElastiCache Memcahced
- multinode for partitioning of data
- no high availability (replication)
- non persistent
- no backup & restore
- multithreaded architecture
describe cache in elasticache
- do not support IAM authentication
- - IAM policies on elasticache are only used for AWS API-lvl security
describe redis cache security
- you can set pw/token when creating a redis cluster
- an extra lvl of security for your cache
- support SSL in flight encryption
describe memcached cache security
- supports SASL based authentication
use case for elasticache
gaming leaderboard
Patterns for ElastiCache
- lazy-loading: all the read data is cached, data can become stale in cache
- write through: adds or update data in the cache when written to a DB
- session store: store temp session data in a cache
