Aurora

Question 1

Basics about Aurora

Answer 1

• DB Engines: PostgreSQL-compatible & MySQL-compatible
• Storage: automatically grows up to 128 TB, 6 copies of data, multi-AZ
• Read Replicas: up to 15 RR, reader endpoint to access them all
• Cross Region RR: entire database is copied (not select tables)
• Load / Offload data directly from / to S3: efficient use of resources
• Backup, Snapshots & Restore: same as RDS

Question 2

Aurora High Availability and Read Scaling

Answer 2

6 copies of your data across 3 AZ:
* 4 copies out of 6 needed for writes
* 3 copies out of 6 need for reads
* Self healing with peer-to-peer replication
* Storage is striped across 100s of volumes

• Automated failover for master in less
  than 30 seconds
• Master + up to 15 Aurora Read
  Replicas serve reads
• Support for Cross Region Replication

Question 3

Aurora Endpoints

Answer 3

• Endpoint = Host Address + Port

Cluster Endpoint (Writer Endpoint)
* Connects to the current primary DB instance in the Aurora cluster
* Used for all write operations in the DB cluster (inserts, updates, deletes, and queries)

Reader Endpoint
* Provides load-balancing for read only connections to all Aurora Replicas in the Aurora cluster
* Used only for read operations (queries)

Custom Endpoint
* Represents a set on DB instances that you choose in the Aurora cluster
* Used when you want to connect to different subsets of DB instances with different capacities and
configurations (e.g., different DB parameter group)

Instance Endpoint
* Connects to a specific DB instance in the Aurora cluster
* Used when you want to diagnosis and fine tune a specific DB instance

Question 4

Aurora Logs

Answer 4

You can monitor the following types
of Aurora MySQL log files:
* Error log
* Slow query log
* General log
* The audit log

These log files are either downloaded or
published to CloudWatch Logs

Question 5

Troubleshooting RDS & Aurora Performance

Answer 5

• Performance Insights: find issues by waits, SQL statements, hosts and users
• CloudWatch Metrics: CPU, Memory, Swap Usage
• Enhanced Monitoring Metrics: at host level, process view, per-second metric
• Slow Query logs

Question 6

Aurora Serverless

Answer 6

• Automated database instantiation and auto
• scaling based on actual usage
• Good for infrequent, intermittent or unpredictable workloads
• No capacity planning needed
• Pay per second, can be more cost-effective

Question 7

Aurora Serverless - Data API

Answer 7

Access Aurora Serverless DB with a simple
API endpoint (no JDBC connection needed)

• Secure HTTPS endpoint to run SQL
  statements
• No persistent DB connections management
• Users must be granted permissions to Data
  API and Secrets Manager (where credentials
  are checked)

Question 8

RDS Proxy for Aurora

Answer 8

Ability to create an additional read-only endpoint that connects to Aurora Read Replicas only

Question 9

Global Aurora

Answer 9

Aurora Cross Region Read Replicas
* Useful for disaster recovery
* Simple to put in place

Aurora Global Database (recommended)
* 1 Primary Region (read / write)
* Up to 5 secondary (read-only) regions, replication lag is
less than 1 second
* Up to 16 Read Replicas per secondary region
* Helps for decreasing latency
* Promoting another region (for disaster recovery) has an
RTO of < 1 minute
* Ability to manage the RPO in Aurora for PostgreSQL

Question 10

Aurora Global – Write Forwarding

Answer 10

Enables Secondary DB Clusters to
forward SQL statements that
perform write operations to the
Primary DB Cluster

• Data is always changed first on the
  Primary DB Cluster, then replicated
  to the Secondary DB Clusters
• Primary DB Cluster always has an
  up-to-date copy of all data
• Reduces the number of endpoints to
  manage

Question 11

Two ways to convert RDS to Aurora

Answer 11

Create a snapshot of the RDS DB instance and restore it in Aurora DB instance
OR
Create an Aurora Read Replica of the RDS DB Instance and then later promote it to an Aurora DB instance