RDS

Question 1

What is the difference between IOPS and throughput?

Answer 1

IOPS is the operations per second you can perform on data. Throughput is the volume of data you can read/write.

IOPS might be more important if you have a huge number of small files. Throughput might be more important if you have a small number of huge files.

Question 2

What is RDS?

Answer 2

Relational Database Service. It’s a fully managed relational database service.

Question 3

How do backups work in RDS?

Answer 3

They’re automatically enabled; daily full backup, transaction logs backed up every 5 minutes. Point-in-time rollbacks (like in Aurora). 7 day retentions, up to 35 days.

Automated snapshots are manually triggered and can be kept indefinitely.

Question 4

How does autoscaling work in RDS?

Answer 4

You can enable autoscaling - set a maximum threshold, and it will upgrade after crossing that point.

Question 5

Tell me about read replicas in RDS.

Answer 5

Can be within AZ, cross-AZ or cross-region. Replication is async, so reads are eventually consistent.

Replicas can be promoted to their own DB.

Read replicas are useful if you want to do analytics against your production DB but don’t want to add load to it.

Question 6

How can I improve HA in RDS?

Answer 6

Configure multi-AZ. It has synchronous replication between databases. Your RDS is referenced by DNS name - if there’s a failure, the DNS points to a replica.

Will not help with scaling, just HA.