Taming an Amazon OpenSearch cost hotspot for a high-growth adtech SaaS
Amazon OpenSearch
AWS CloudFormation
Cost ExplorerShared anonymously — the customer’s name is held by VeUP and available on request.
For a UK shoppable-content adtech SaaS, VeUP attacked the Amazon OpenSearch Service cost hotspot — the largest line item on its AWS bill — with index-lifecycle and storage-tiering policies, Archera commitments, a Cost-Optimization Well-Architected Review, and a CloudFormation cost dashboard.
The challenge
Rapid growth drove the customer’s AWS costs up, concentrated in an Amazon OpenSearch Service tier (search + log analytics) that had become the single largest line item on the bill — and it grew with index volume. The team needed to reduce and stabilize that cost without losing search/analytics capability, plus an independent architecture review and durable cost visibility as it scaled.
The solution
A managed-FinOps and Well-Architected engagement centered on the Amazon OpenSearch Service tier: Index State Management lifecycle policies, UltraWarm/Cold storage tiering, and replica right-sizing so cost tracks data value rather than raw accumulation; Archera Savings-Plans/Reserved-Instances commitment coverage; a Well-Architected Review weighted to the Cost Optimization pillar producing a prioritized remediation backlog; and a cost/observability dashboard delivered via AWS CloudFormation over Amazon CloudWatch and AWS Cost Explorer, governed with AWS IAM Identity Center, AWS Organizations, AWS KMS and Amazon VPC.
Production outcomes
| KPI | Result |
|---|---|
| Production outcomes | OpenSearch index-lifecycle and storage-tiering policies went live, with Archera commitment coverage layered on top, so cost tracks data value instead of raw accumulation. A Cost-Optimization-weighted Well-Architected Review produced a prioritized remediation backlog, and a CloudFormation cost/observability dashboard now lets the customer track OpenSearch and overall spend by service. The realized reduction sits in the customer’s own Cost Explorer, available on request. |
| Engagement window | The platform ran live on AWS with VeUP from October 2024, and the Well-Architected Review was delivered in March 2026. The account has since moved on — this is a historical engagement. |
| Cost / TCO posture | The engagement was a FinOps program against the OpenSearch hotspot: ISM lifecycle + UltraWarm/Cold tiering + replica right-sizing (cost tracks data value) layered with Archera commitment coverage, and a CloudFormation dashboard for durable per-service cost visibility. The realized reduction is the customer’s own Cost Explorer figure. |
| Lessons & continuation | On high-growth search/analytics SaaS, the OpenSearch tier is often the runaway line item — index lifecycle + storage tiering + replica right-sizing attack it before commitment coverage; a CloudFormation cost dashboard turns a one-time FinOps review into a durable mechanism. |
Amazon CloudWatch
AWS Organizations
AWS IAM Identity Center
AWS KMSArchitecture
Where it started
Pre-engagement baselineMarketing & Advertising — adtech / shoppable-content SaaS · United KingdomThe search and log-analytics domain ran every index on on-demand hot storage, with indexes growing ~10%+ per period.
No ISM lifecycle and no UltraWarm/Cold tiers — cost tracked index age and volume, not data value.
No Savings Plans or Reserved Instance coverage anywhere in the account, against a growing, predictable baseline.
No consolidated cost dashboard — limited per-service visibility, with cost hotspots surfacing late and reactively.
Security, reliability, and cost-optimization gaps had no prioritized owner or sequence before the review.
An existing production workload — the engagement was a cost and architecture review, and this is the baseline it started from.