Skip to main content

AWS Fundamentals, RDS, Aurora, ElastiCache

info

These were the topics I created flashcards for (Remnote) and would revise them using spaced repetition. The formatting is an export from Remnote.

  • Amazon Relational Database Service, collection of \{\{managed\}\} services to \{\{deploy\}\}, \{\{operate\}\} and \{\{scale\}\} databases in the cloud. Choose from \{\{seven\}\} database engines available e.g. MySQL, PostgreSQL, SQL Server.
  • RDS backups
    • automated backups are enabled by default
    • the two types of backups are?
      • automated backups
        • the default backup retention period?―7 days (if created by console).
        • what else is backed up?―transaction logs
        • what kind of restore capability does transaction logs give you?―Point in Time Recovery.
        • what's the maximum you can set the backup retention period to?―35 days.
        • how do you disable automated backups?―set backup retention period to '0'.
      • snapshots (manual)
        • who initiates snapshot backups?―user-initiated.
        • how long are snapshots retained?―indefinite.
  • RDS Scaling
    • what are the 3 types of scaling available with RDS? ↓
      • Vertical ‒ Compute Instance
      • Horizontal ‒ Storage Auto Scaling
      • Read Replicas ‒ Read capability
  • Read Replicas
    • max RR's per Region?―5.
    • data replication is " \{\{ __eventually__ \}\} consistent" i.e. \{\{ __asynchronous__ \}\}.
    • data transfer costs: out to the internet; in the same Region; and Region to Region ‒ which one costs nothing?―in the same Region.
  • Multi-AZ
    • what is the main use-case for MAZ?―Disaster Recovery (DR)
    • data replication between primary and secondary DB is done..?―synchronously
    • how handles the failover between Primary and Secondary?―RDS. It is automated.
    • can I convert a Read Replica into a Secondary, MAZ node?―Yes.
    • how much downtime can I expect transferring a Single-AZ into a Multi-AZ setup?―None.
    • can I ssh or otherwise access the Secondary DB?―No.
  • RDS Custom
    • Applies to which 2 database types?― ↓
      • Oracle
      • Microsoft SQL Server
    • What two main differences between RDS and RDS Custom?
      • ssh ‒ you can ssh into the underlying EC2 instance.
      • config DB ‒ you can configure the underlying database.
    • Best Practice for doing backups on RDS Custom? ↓
      • disable automation's before taking a snapshot
  • Aurora
    • Supports, and is faster than which 2 database engines?― ↓
      • MySQL (5x)
      • PostgreSQL (3x)
    • Is it open source?―No.
    • Storage auto scales up to what max (TiB)?―128TiB.
    • In a normal setup, how many masters can an Aurora cluster have?―one.
    • how many RRs max can a cluster have, in a single Region?―15.
    • Aurora makes \{\{6\}\} copies of your data across \{\{3\}\} Availability Zones to make your data really \{\{durable\}\}.
    • If I used mixed sized Instances in my Aurora Read Replicas to provide different levels of compute power for different types of work, what would I use to ensure only specific requests access these instances?―Custom Endpoints.
    • If my workloads were unpredictable but needed high compute power, and I wanted to optimise costs when using Aurora, what feature could I use to help me?―Aurora Serverless.
    • Disaster Recovery & High-Availability #[[Disaster Recovery]]
      • What Disaster Recovery or High-Availability feature does Aurora have to ensure zero downtime on DB write operations for its clusters?―Multi Master Aurora Clusters.
    • Backups
      • Automated Backups can be disabled on RDS and Aurora? True or False?―False. Only on RDS.
      • What is the default backup retention period for Aurora backups?―1 day.
      • What is the max you can configure backup retention period for Aurora backups?―35 days (same as RDS).
      • When migrating an Aurora database using S3, what tool is used to create the Aurora database backup?―Percona.
      • Can you restore a DB cluster snapshot into an existing DB cluster?―No. A new DB cluster is created when you restore.
      • What are the three ways of creating a Aurora DB instance? ↓
        • Restore from snapshot or backup creates a new DB
        • Backup with percona, send to S3, restore into new Aurora DB
        • DB clone
    • Security
      • Four ways RDS is secure? ↓
        • Network isolation via VPC
        • Encryption using KMS on RDS instance storage (enabled by default)
        • IAM for resource-based permissions
        • CloudWatch for Audit logging.
  • RDS Proxy (Connections)
    • What does using RDS Proxy mean in terms of code changes?―None.
    • Four benefits of RDS Proxy? ↓
      • Reduce stress on the DB
      • Failover improvements
      • Connection Management between user and application.
      • Authentication (IAM) available for users calling the DB.
  • Elasticache (Content)
    • What are the two cache types available from Elasticache? ↓
      • Redis
      • Memcached
    • What does using Elasticache mean in terms of code changes?―There will be code changes.
    • Can you use IAM Auth for Redis or Memcached?―No.
    • What can you use for Auth instead for Redis and Memcache? ↓
      • Redis AUTH for Redis
      • SASL for Memcached.
    • What are the THREE Elasticache caching strategies (patterns)?― ↓
      • Lazy Loading (LL)
        • HIT, MISS + UPDATE
      • Write-through (WT)
        • 2 x PUT (cache & DB)
      • TTL
        • expire + retrieve