AWS : Database Specialty Exam — Part 3

A Quick Review for Management and Operations

Pisit J.

Published in

Sum up As A Service

2 min readSep 10, 2022

Part 3: Management and Operations (18% of exam)

Determine appropriate maintenance window strategies
Determine backup and restore strategies
Implement configuration changes
Automate operational tasks

1 — What must the Database Specialist concern after restoring DynamoDB table ?

You must manually re-apply some configuration after restoring

Auto scaling policies
AWS Identity and Access Management (IAM) policies
Amazon CloudWatch metrics and alarms
Tags
Stream settings
Time to Live (TTL) settings

2 — A Database Specialist attempts to delete the last DB instance in the Amazon Aurora cluster. However, the action throws out an error and fails.

What is most likely causing the issue ?

Deletion protection option is enabled.

Note — You can enable deletion protection so that users can’t delete a DB cluster whether you perform the operation from the console, the CLI, or the API. To be certain that you can delete the cluster, modify the cluster, and disable deletion protection.

Since there is only one remaining instance in the cluster, and it will try to delete the cluster too.

https://aws.amazon.com/premiumsupport/knowledge-center/rds-error-delete-aurora-cluster/

3 — A Database Specialist wants to build a proof of concept for their Amazon Aurora cluster to demonstrate the effect of a disk failure event on the application’s performance.

How to simulate this event ?

Use fault injection queries.

Note — Fault injection queries are issued as SQL commands to an Amazon Aurora instance and they enable you to schedule a simulated occurrence of one of the following events:

A crash of a writer or reader DB instance
A failure of an Aurora Replica
A disk failure
Disk congestion

https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/AuroraMySQL.Managing.FaultInjectionQueries.html

4 — How can you ensure that background write-operation, like during a snapshot, do not impact performance of ElastiCache for Redis cluster ?

Set reserved-memory-percent parameter to 25%

https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/BestPractices.BGSAVE.html

What will happen when the Amazon DynamoDB table is backed up ?

backup is created asynchronously
backup does not guarantee causal consistency across items
All backups in DynamoDB work without consuming any provisioned throughput on the table.
While a backup is in progress, you cannot do the following: Pause or cancel the backup operation, Delete the source table of the backup, Disable backups on a table if a backup for that table is in progress.

https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_CreateBackup.html

Reference

[Udemy] AWS Certified Database Specialty Practice Exam