Aurora Flashcards
What is Aurora?
It’s a cloud-optimized SQL database, compatible with postgres and mysql drivers.
Why would you choose Aurora?
It costs 20% more than RDS, but is way more performant. Any time you need a relational database, consider Aurora.
Advantages:
3-5x more performant
storage automatically grows by 10GB, up to 64TB
Can have more replicas, with faster replication process
HA, fast failover
So, mostly managed for you, but you’re still provisioning a machine type for it (and this doesn’t change automatically unless you enable auto scaling).
Is Aurora within one AZ, cross-AZ, or cross-region?
It’s cross-az by default, but can be cross-region if you enable that or use Aurora Global Database.
If I want higher aurora availability, what can I do?
You can enable cross-region replication, but the recommended approach is use Aurora Global Database.
Explain HA in Aurora.
You have 6 copies of your data across 3 AZ. There’s self-healing, and it’s striped across 100s of volumes.
If you want better HA you can pay for cross-region replication (or aurora global database).
You may want to consider enabling ‘multi-master’ for instant failover of the master.
How do backups work with Aurora?
AWS does automatic, regular backups (using EC2 under the hood). This allows you to backtrack to a specific point in time. It’s super granular (within seconds supposedly).
How do reads/writes work with Aurora?
Only the master (with a writer endpoint) does writes. New writes are replicated to other read replicas.
Read requests are load-balanced at the connection level. When you hit the read endpoint, it connects you to a replica.
What is Aurora Serverless, and what is it useful for?
Automated DB instantiation, and auto-scaling based on actual usage. Good for infrequent, intermittent or unpredictable workloads. No cap planning, pay per second. Gets really expensive if there’s consistent use.
What is Aurora auto scaling?
You can enable this to automatically scale up replicas if existing ones have high CPU usage
What happens if the write instance fails?
A read replica needs to be promoted to master, though this can take some time. If you need immediate failover, pay for “multi-master” (which makes every replica do R/W).
How does Aurora Global Database work?
You have one primary region for read/write, with multiple read-only regions. Replication lag is less than 1 second. Each secondary region can have multiple read replicas.
Gives you decreased latency.
Promoting another region (disaster recovery) has a RTO of less than a minute.
