RDS instance has Multi-AZ enabled

Check ID: rds_instance_multi_az
Provider: AWS
Service: rds
Severity: MEDIUM
Categories: resilience
Resource type: AwsRdsDbInstance

What this check verifies

RDS DB instances are evaluated for Multi-AZ configuration, either enabled on the instance or inherited from the associated DB cluster.

Risk

Without Multi-AZ, an Availability Zone or instance failure can cause extended downtime and rely on restores, risking loss of recent writes. This degrades availability and may affect integrity, interrupting applications and breaching SLAs.

Recommendation

Apply fault-tolerance and redundancy principles: enable Multi-AZ for production RDS workloads. Choose one standby or two readable standbys based on RTO/RPO and performance needs. Regularly test failover, monitor configuration drift, and allow exceptions only with documented, risk-based approval.

Remediation

CLI
Terraform
Native IaC
Dashboard steps

aws rds modify-db-instance —db-instance-identifier <db_instance_id> —multi-az —apply-immediately

# Enable Multi-AZ on an RDS DB instance
resource "aws_db_instance" "example" {
  multi_az = true  # Critical: enables Multi-AZ to pass the check
}

# CloudFormation: enable Multi-AZ on an existing RDS DB instance
Resources:
  RDSInstance:
    Type: AWS::RDS::DBInstance
    Properties:
      MultiAZ: true  # Critical: enables Multi-AZ to pass the check

References

Where this check fires

This check runs on every scheduled scan against your AWS account. Findings appear at Cloud Security → Findings filterable by Check ID = rds_instance_multi_az. To re-evaluate after a fix, hit Run now on the account’s schedule under Cloud Security → Schedules — the next scan re-checks this control and marks the finding fixed or keeps it persistent.

← Back to AWS checks

RDS instance has minor version upgrade enabled RDS instance is not publicly exposed to the Internet

​What this check verifies

​Risk

​Recommendation

​Remediation

​References

​Where this check fires

What this check verifies

Risk

Recommendation

Remediation

References

Where this check fires