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URL: https://dev.to/yash_step2dev/aurora-serverless-v2-vs-rds-when-to-use-which-4k3e

⇱ Aurora Serverless v2 vs RDS: when to use which - DEV Community

Aurora Serverless v2 vs RDS: when to use which (with real cost comparisons)

The key difference 

RDS (provisioned): Fixed capacity, fixed cost, consistent performance
Aurora Serverless v2: Scales between min/max ACU, minimum 0.5 ACU always running

Cost comparison (PostgreSQL, us-east-1) 

Scenario 1: Low-traffic dev database (constant)
 RDS db.t4g.micro: $11.52/month
 Aurora Serverless v2 0.5: $43.20/month
 Verdict: RDS wins 4:1

Scenario 2: Predictable production (sized for peak)
 Aurora Serverless v2: ~$144/month
 RDS db.t4g.medium: ~$46.80/month
 Verdict: RDS wins again

Scenario 3: Truly unpredictable spikes (rare 16 ACU bursts)
 Aurora Serverless v2: ~$50-80/month average
 RDS sized for 16 ACU: $346/month constantly
 Verdict: Aurora Serverless v2 wins

When Aurora Serverless v2 is right

  • Truly unpredictable workloads (traffic that 10xs without warning)
  • Multi-tenant SaaS (many per-tenant databases, mostly idle)
  • Dev databases where you want near-zero cost

When standard RDS is better

  • Predictable steady-state load (almost everything)
  • Cost-sensitive: db.t4g.micro is dramatically cheaper
  • You need specific PostgreSQL extensions
  • Latency-sensitive: RDS has more consistent p99

Terraform for Aurora Serverless v2 

resource "aws_rds_cluster" "main" {
 engine = "aurora-postgresql"; engine_mode = "provisioned"
 serverlessv2_scaling_configuration { min_capacity = 0.5; max_capacity = 16 }
}
resource "aws_rds_cluster_instance" "main" {
 instance_class = "db.serverless" # Required for Serverless v2
 cluster_identifier = aws_rds_cluster.main.id
}

Step2Dev supports both RDS and Aurora in project setup.

👉 step2dev.com

What database setup have you found most cost-effective at your scale?