AWS Trusted Advisor
Service 44

AWS Trusted Advisor

MonitoringAdvisoryCost

Trusted Advisor scans your account against published best-practice checks drawn from AWS's operational experience — idle EC2 instances, unrestricted security groups, unused IAM keys, service limits about to be hit — and reports findings in five categories: cost optimization, performance, security, fault tolerance, and service limits.

It is one of the oldest AWS opinions on running an account well and remains a useful weekly review even alongside newer services like Security Hub.

The Five Categories

Cost Optimization flags idle and underutilized resources, unattached EBS volumes, and Reserved Instance / Savings Plan opportunities. Performance identifies bottlenecks like over-utilized instances and wrong cache-hit ratios. Security highlights open security groups, weak IAM password policies, root access keys, and public buckets.

Fault Tolerance finds single points of failure — EBS volumes without snapshots, single-AZ Auto Scaling Groups, RDS without Multi-AZ. Service Limits tracks how close you are to quotas, since hitting one in production is an avoidable outage.

Support-Plan Tiers

The free tier (every account) covers six core security checks plus a service-limits summary. Business and Enterprise Support unlock all checks across all categories, on-demand refresh, Trusted Advisor Priority (curated findings from the AWS account team), and EventBridge integration.

For Business/Enterprise accounts, a weekly review is the standard practice; for free-tier accounts, Security Hub plus custom Config rules covers more ground.

Trusted Advisor vs Security Hub vs Cost Explorer

Trusted Advisor — a broad best-practices checklist across cost, performance, security, fault tolerance, and limits.

Security Hub — deeper, continuous security posture and finding aggregation — broader than Trusted Advisor's security checks.

Cost Explorer — detailed spend analysis and trends — Trusted Advisor only flags specific idle resources.

Common Mistakes
  • Ignoring the Service Limits category until a quota is hit in production, causing an avoidable outage.
  • Treating Trusted Advisor's security checks as full coverage instead of pairing them with Security Hub.
  • Expecting full Trusted Advisor on the free tier — most checks require Business or Enterprise Support.
  • Reviewing it once and never again, so findings drift back as the account changes.
  • Using it for deep cost analysis instead of Cost Explorer and Cost and Usage Reports.
  • Dismissing fault-tolerance findings, which are the best protection against avoidable AZ-loss outages.
Best Practices
  • Review Trusted Advisor weekly on Business or Enterprise Support accounts.
  • Wire the Service Limits category into EventBridge to alert before you hit a quota.
  • Use it for cost reviews alongside Cost Explorer — it finds specific idle resources.
  • Combine with Security Hub for fuller security coverage.
  • Take fault-tolerance findings seriously.
Comparable services GCP Active Assist / RecommenderAzure Azure Advisor

Knowledge Check

What does the Service Limits category of Trusted Advisor help prevent?

  • Avoidable outages from hitting an AWS service quota in production
  • Data leaks from S3 buckets accidentally left open to public read access
  • Slow database queries from unindexed tables
  • Surprise cross-AZ data-transfer charges

What does the free tier of Trusted Advisor include?

  • Six core security checks plus a service-limits summary
  • The full set of checks across all five categories
  • Curated Trusted Advisor Priority recommendations
  • Nothing at all — every check requires Business Support

How does Trusted Advisor relate to Security Hub for security?

  • Trusted Advisor's security checks are a useful baseline; Security Hub provides broader, deeper coverage
  • They are identical and run exactly the same set of security checks against the same compliance standards
  • Trusted Advisor fully replaces the need for Security Hub in a mature security program
  • Security Hub only checks cost optimization, not security

For deep analysis of where your spend is going, which tool fits better than Trusted Advisor?

  • Cost Explorer and Cost and Usage Reports
  • CloudTrail management and data event logs
  • AWS Config conformance packs and rules
  • Systems Manager Session Manager shell access

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