Databases: Amazon RDS and ElastiCache

Question 1

Automated failover of a multi-AZ DB occurred

Answer 1

This may be due to storage failure on primary DB or the instance type could have been changed

Question 2

Need to encrypt unencrypted RDS database

Answer 2

Take a snapshot, encrypt it, then restore a new encrypted instance from the snapshot

Question 3

RDS DB query latency is high and CPU utilization is at 100%

Answer 3

Scale up with larger instance type

Question 4

Need to share RDS DB snapshots across different accounts. Data must be encrypted

Answer 4

Use an AWS KMS key for encryption and update key policy to grant accounts with access then share snapshot

Question 5

DB needs to be made HA to protect against failure and updates cannot impact users in business hours

Answer 5

Change to Multi-AZ outside of business hours

Question 6

Need to protect RDS databases against table corruption within a 30 day window of protection

Answer 6

Enable automated backups and set the appropriate retention period

Question 7

Shared Responsibility Model

Answer 7

AWS is responsible for maintenance, patches and other updates for Aurora DB

Question 8

AuroraReplicaLagMaximum is high for DB on eCommerce site. What affect could this have?

Answer 8

may result in cart not updating correctly (inconsistency)

Question 9

EC2 connects to RDS instance and fails with: “Error Establishing a Database Connection”

Answer 9

Web server may be using certificate validation and RDS does not trust the certificate. Or, the DB security group does not have the correct ingress rule

Question 10

Aurora DB is hitting 100% CPU. Read-heavy app with many lookups

Answer 10

Add Aurora Replicas and use a Reader Endpoint for product table lookups

Question 11

Database is running MySQL on Amazon EC2. Need to increase availability and durability without changing application

Answer 11

Use Aurora MySQL and configure an Aurora Replica in another AZ

Question 12

Reporting job runs against RDS instance and is causing performance issues

Answer 12

Create a read replica and point the reporting job to the read replica endpoint

Question 13

Backup of RDS instance must be copied regularly to another account for testing

Answer 13

Create a snapshot with create-db-snapshot CLI, share with other account, then create a copy in that account

Question 14

MySQL database on RDS must be patched due to a security vulnerability. Who is responsible?

Answer 14

AWS is responsible for patching Amazon RDS database instances

Question 15

Reporting job runs against RDS instance and is causing performance issues

Answer 15

Create a read replica and point the reporting job to the read replica endpoint

Question 16

How can a Redis cluster be scaled to improve read times

Answer 16

Scale horizontally by adding shards

Question 17

High CPU on a Memcached cluster

Answer 17

Options are to add additional nodes to cluster or vertically scale the node types

Question 18

ElastiCache Memcached storing session state. Performance poor, eviction count metrics are high

Answer 18

Scale the cluster by adding additional nodes

Question 19

A Memcached cluster is experiencing increased traffic, need to change to larger node type

Answer 19

Create a new cache cluster with the new node type using the CreateCacheCluster API