Chapter 2 of 5 · AWS SOA-C03
Reliability and Continuity
Auto Scaling, load balancing, Multi AZ data tiers, disaster recovery strategies and backup and restore.
- 5topics
- 24 minfast track
- 3diagrams and exhibits
- 22%of the exam
Topics in this chapter
Take them in order, or jump to the one you need.
- 1Auto Scaling and ElasticityBuild elastic workloads with EC2 Auto Scaling groups, scaling policies, lifecycle hooks and warm pools, and know how Lambda and…5 min
- 2Load Balancing and Multi AZ DesignChoose between Application, Network and Gateway Load Balancers, set health checks and cross zone behaviour, and design for an…5 min
- 3Database and Storage ResilienceCompare RDS Multi AZ, read replicas, Aurora, DynamoDB global tables, ElastiCache, S3 and EFS so data survives instance, AZ and…Diagram5 min
- 4Disaster Recovery StrategiesUnderstand RTO and RPO, compare backup and restore, pilot light, warm standby and active active, and use Route 53 failover and…Diagram4 min
- 5Backup and Restore StrategiesPlan backups with AWS Backup, EBS snapshots and Data Lifecycle Manager, RDS point in time recovery, S3 versioning and DynamoDB…Diagram5 min
About this chapter
What this chapter covers
Reliability is about keeping a workload running when load changes or parts fail, and getting it back when something big goes wrong. This chapter follows the reliability and business continuity domain of the AWS Certified CloudOps Engineer Associate (SOA-C03) outline.
It moves from small, automatic responses to large, planned ones. Scaling and load balancing handle changing demand and single failures, Multi AZ and replication protect the data tier, and disaster recovery and backups cover the worst cases.
The chapter has three outline topics, and they are spread across five pages. High availability is the broadest topic, so it takes three pages.
How the topics fit together
Each page deals with a bigger failure than the one before.
- Auto Scaling adds and removes capacity and replaces unhealthy instances.
- Load balancers and Multi AZ keep traffic away from failed targets and zones.
- Database resilience chooses between Multi AZ, read replicas and cross Region copies.
- Disaster recovery picks a strategy from the required RTO and RPO.
- Backup and restore protects against mistakes and attacks that replication copies.
Many questions are a matching exercise. Identify the failure (instance, AZ, Region, human error) and pick the feature built for that failure.
How to use these pages
Each topic page has the same shape, so you can skim for what you need.
- What it is: the idea in plain words.
- How it works: the mechanism, with diagrams and example commands.
- What to remember for the exam: the facts to memorise.
- Common mistakes: the classic traps.
- Check yourself: three questions to test your understanding.
Keep the two definitions RTO and RPO in mind from the start, because they decide almost every design choice in the last two pages.
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