Category	Example	Use Case
Standard	db.m6g.large	General purpose
Memory Optimized	db.r6g.large	High memory workloads
Burstable	db.t3.medium	Variable workloads, dev/test

Storage Types

Type	IOPS	Use Case
gp3	3,000-16,000	Most workloads
io1/io2	Up to 256,000	High-performance OLTP
magnetic	N/A	Legacy, avoid

Multi-AZ Deployments

Multi-AZ Instance: Synchronous standby in different AZ
Multi-AZ Cluster: One writer, two reader instances (Aurora-like)

Read Replicas

Asynchronous copies for read scaling. Can be cross-region.

Common Patterns

Create a PostgreSQL Instance

AWS CLI:

# Create DB subnet group
aws rds create-db-subnet-group \
  --db-subnet-group-name my-db-subnet-group \
  --db-subnet-group-description "Private subnets for RDS" \
  --subnet-ids subnet-12345678 subnet-87654321

# Create security group (allow PostgreSQL from app)
aws ec2 create-security-group \
  --group-name rds-postgres-sg \
  --description "RDS PostgreSQL access" \
  --vpc-id vpc-12345678

aws ec2 authorize-security-group-ingress \
  --group-id sg-rds12345 \
  --protocol tcp \
  --port 5432 \
  --source-group sg-app12345

# Create RDS instance
aws rds create-db-instance \
  --db-instance-identifier my-postgres \
  --db-instance-class db.t3.medium \
  --engine postgres \
  --engine-version 16.1 \
  --master-username admin \
  --master-user-password 'SecurePassword123!' \
  --allocated-storage 100 \
  --storage-type gp3 \
  --db-subnet-group-name my-db-subnet-group \
  --vpc-security-group-ids sg-rds12345 \
  --multi-az \
  --backup-retention-period 7 \
  --storage-encrypted \
  --no-publicly-accessible

boto3:

import boto3

rds = boto3.client('rds')

response = rds.create_db_instance(
    DBInstanceIdentifier='my-postgres',
    DBInstanceClass='db.t3.medium',
    Engine='postgres',
    EngineVersion='16.1',
    MasterUsername='admin',
    MasterUserPassword='SecurePassword123!',
    AllocatedStorage=100,
    StorageType='gp3',
    DBSubnetGroupName='my-db-subnet-group',
    VpcSecurityGroupIds=['sg-rds12345'],
    MultiAZ=True,
    BackupRetentionPeriod=7,
    StorageEncrypted=True,
    PubliclyAccessible=False
)

Create Read Replica

aws rds create-db-instance-read-replica \
  --db-instance-identifier my-postgres-replica \
  --source-db-instance-identifier my-postgres \
  --db-instance-class db.t3.medium \
  --availability-zone us-east-1b

Take a Snapshot

aws rds create-db-snapshot \
  --db-snapshot-identifier my-postgres-snapshot-2024-01-15 \
  --db-instance-identifier my-postgres

Restore from Snapshot

aws rds restore-db-instance-from-db-snapshot \
  --db-instance-identifier my-postgres-restored \
  --db-snapshot-identifier my-postgres-snapshot-2024-01-15 \
  --db-instance-class db.t3.medium \
  --db-subnet-group-name my-db-subnet-group \
  --vpc-security-group-ids sg-rds12345

Point-in-Time Recovery

aws rds restore-db-instance-to-point-in-time \
  --source-db-instance-identifier my-postgres \
  --target-db-instance-identifier my-postgres-pitr \
  --restore-time 2024-01-15T10:30:00Z \
  --db-instance-class db.t3.medium

Modify Instance

# Change instance class (with downtime)
aws rds modify-db-instance \
  --db-instance-identifier my-postgres \
  --db-instance-class db.m6g.large \
  --apply-immediately

# Scale storage (no downtime)
aws rds modify-db-instance \
  --db-instance-identifier my-postgres \
  --allocated-storage 200 \
  --apply-immediately

Connect with IAM Authentication

import boto3
import psycopg2

rds = boto3.client('rds')

# Generate auth token
token = rds.generate_db_auth_token(
    DBHostname='my-postgres.abc123.us-east-1.rds.amazonaws.com',
    Port=5432,
    DBUsername='iam_user',
    Region='us-east-1'
)

# Connect
conn = psycopg2.connect(
    host='my-postgres.abc123.us-east-1.rds.amazonaws.com',
    port=5432,
    database='mydb',
    user='iam_user',
    password=token,
    sslmode='require'
)

CLI Reference

Instance Management

Command	Description
`aws rds create-db-instance`	Create instance
`aws rds describe-db-instances`	List instances
`aws rds modify-db-instance`	Modify settings
`aws rds delete-db-instance`	Delete instance
`aws rds reboot-db-instance`	Reboot instance
`aws rds start-db-instance`	Start stopped instance
`aws rds stop-db-instance`	Stop instance

Backups

Command	Description
`aws rds create-db-snapshot`	Manual snapshot
`aws rds describe-db-snapshots`	List snapshots
`aws rds restore-db-instance-from-db-snapshot`	Restore from snapshot
`aws rds restore-db-instance-to-point-in-time`	Point-in-time restore
`aws rds copy-db-snapshot`	Copy snapshot

Replicas

Command	Description
`aws rds create-db-instance-read-replica`	Create read replica
`aws rds promote-read-replica`	Promote to standalone

Best Practices

Security

Never make publicly accessible — use VPC and security groups
Enable encryption at rest (KMS) and in transit (SSL)
Use IAM authentication for application access
Store credentials in Secrets Manager with rotation
Use parameter groups to enforce SSL

# Enforce SSL in PostgreSQL
aws rds modify-db-parameter-group \
  --db-parameter-group-name my-pg-params \
  --parameters "ParameterName=rds.force_ssl,ParameterValue=1,ApplyMethod=pending-reboot"

Performance

Right-size instances — monitor CPU, memory, IOPS
Use gp3 for cost-effective performance
Enable Performance Insights for query analysis
Use read replicas for read scaling
Optimize queries — check slow query log

High Availability

Enable Multi-AZ for production
Use Aurora for mission-critical workloads
Configure appropriate backup retention
Test failover periodically
Monitor replication lag for replicas

Cost Optimization

Use Reserved Instances for steady-state workloads
Stop dev/test instances when not in use
Delete old snapshots regularly
Right-size instance classes

Troubleshooting

Cannot Connect

Causes:

Security group not allowing access
Instance not in VPC subnet
SSL required but not used
Wrong endpoint/port

Debug:

# Check security group
aws ec2 describe-security-groups --group-ids sg-rds12345

# Check instance status
aws rds describe-db-instances \
  --db-instance-identifier my-postgres \
  --query "DBInstances[0].{Status:DBInstanceStatus,Endpoint:Endpoint}"

# Test connectivity from EC2
nc -zv my-postgres.abc123.us-east-1.rds.amazonaws.com 5432

High CPU/Memory

Debug:

# Enable Enhanced Monitoring
aws rds modify-db-instance \
  --db-instance-identifier my-postgres \
  --monitoring-interval 60 \
  --monitoring-role-arn arn:aws:iam::123456789012:role/rds-monitoring-role

# Enable Performance Insights
aws rds modify-db-instance \
  --db-instance-identifier my-postgres \
  --enable-performance-insights \
  --performance-insights-retention-period 7

Solutions:

Scale up instance class
Optimize slow queries
Add read replicas
Check for locking/blocking

Storage Full

Symptom: Instance becomes unavailable

Prevention:

# Enable storage autoscaling
aws rds modify-db-instance \
  --db-instance-identifier my-postgres \
  --max-allocated-storage 500

# Set CloudWatch alarm
aws cloudwatch put-metric-alarm \
  --alarm-name "RDS-Storage-Low" \
  --metric-name FreeStorageSpace \
  --namespace AWS/RDS \
  --dimensions Name=DBInstanceIdentifier,Value=my-postgres \
  --statistic Average \
  --period 300 \
  --threshold 10000000000 \
  --comparison-operator LessThanThreshold \
  --evaluation-periods 2 \
  --alarm-actions arn:aws:sns:us-east-1:123456789012:alerts

Replication Lag

Monitor:

aws cloudwatch get-metric-statistics \
  --namespace AWS/RDS \
  --metric-name ReplicaLag \
  --dimensions Name=DBInstanceIdentifier,Value=my-postgres-replica \
  --start-time $(date -d '1 hour ago' -u +%Y-%m-%dT%H:%M:%SZ) \
  --end-time $(date -u +%Y-%m-%dT%H:%M:%SZ) \
  --period 60 \
  --statistics Average

Causes:

Replica instance too small
Heavy write load
Network issues
Long-running queries on replica

Storage Types

Multi-AZ Deployments

Read Replicas

Common Patterns

Create a PostgreSQL Instance

Create Read Replica

Take a Snapshot

Restore from Snapshot

Point-in-Time Recovery

Modify Instance

Connect with IAM Authentication

CLI Reference

Instance Management

Backups

Replicas

Best Practices

Security

Performance

High Availability

Cost Optimization

Troubleshooting

Cannot Connect

High CPU/Memory

Storage Full

Replication Lag

References

rds

AWS RDS

Table of Contents

Core Concepts

DB Instance Classes