Cloud

save cloud costs without breaking performance: a checklist for engineers

save cloud costs without breaking performance: a checklist for engineers

I’ve spent years helping teams balance two competing forces: keeping cloud bills from spiralling out of control while preserving — or even improving — application performance. It sounds like a compromise in principle, but with the right measurement and a practical checklist you can achieve big savings without slowing users down. Below I share the concrete tactics I use when auditing cloud spend, plus the rationale and quick wins engineers can implement in hours or days.

Start with measurement: know your baseline

You can’t optimise what you don’t measure. My first step is always to assemble a clear baseline of cost and performance.

  • Collect costs broken down by service, project, and environment (prod, staging, dev).
  • Correlate cost with performance metrics: latency, error rate, throughput, and user-facing KPIs.
  • Use cloud provider tools (AWS Cost Explorer, Azure Cost Management, GCP Billing) plus an external tool like CloudHealth, Spot.io, or open-source prometheus+grafana for observability.
  • When I do this I aim to answer: which resources are the most expensive, which are steadily increasing, and which have low utilisation but high cost. That directs the rest of the checklist.

    Rightsize compute: match instance types and counts to real demand

    Rightsizing is the low-hanging fruit. Teams often overprovision “just in case.” I prefer rightsizing with data.

  • Analyse CPU, memory, and network utilisation over realistic windows (business week, peak season).
  • Scale vertically only when necessary — try smaller instance families first; sometimes a different instance type delivers better price/performance.
  • Implement horizontal autoscaling for stateless services: set sensible min/max ranges and use target tracking for robust behaviour.
  • On AWS I commonly replace general-purpose m5 instances with burstable t3/t4 for low-throughput services, or opt for c6i when CPU-bound. On GCP, N2/N1 family swaps often help. Be careful: switching families requires testing to avoid noisy-neighbour or network perf regressions.

    Use Spot/Preemptible instances for non-critical workloads

    Spot (AWS) / Preemptible (GCP) instances can reduce compute costs by 60–90% when used correctly.

  • Run CI pipelines, batch processing, data transformations, and non-critical worker pools on spot instances.
  • Architect for interruption: use checkpointing, idempotent tasks, or a mix of on-demand + spot fleets.
  • Consider managed services like AWS Batch, Google Dataproc, or Kubernetes Cluster Autoscaler with mixed instances to simplify ops.
  • Pick the right storage class and lifecycle policies

    Storage is one of the sneakiest line items. I always review how accessible the data needs to be and for how long.

  • Classify data: hot (frequent access), warm (occasional), cold (rare), and archive.
  • Apply lifecycle policies: move older objects to infrequent access, then to Glacier/Coldline/Archive as appropriate.
  • Clean up orphaned snapshots, unused AMIs, and unattached volumes — they cost money while doing nothing.
  • For example, moving infrequently accessed logs to S3 Infrequent Access and deleting snapshots after retention windows can produce immediate savings.

    Reduce data transfer costs

    Data egress and cross-zone transfers pile up in distributed systems. The fix is both architectural and tactical.

  • Co-locate services that exchange lots of data in the same region and availability zone when possible.
  • Use Content Delivery Networks (CDNs) like CloudFront or Cloudflare to cache static assets at the edge.
  • Compress payloads, use efficient serialization (Protobuf instead of JSON where it makes sense), and avoid chatty APIs.
  • Choose managed services judiciously

    Managed services often save engineering time but sometimes at a premium. I weigh total cost of ownership, not just hourly price.

  • For operationally expensive services (databases, message queues), managed offerings might reduce labour and downtime costs.
  • For simple workloads, consider self-managed or lightweight alternatives. E.g., a tiny Redis on EC2 might be cheaper than a large managed Redis if you can afford the ops overhead.
  • Track licences and add-on charges in SaaS-managed services — they’re a hidden source of cost creep.
  • Optimize databases and caching

    Databases are both performance-critical and expensive. Small changes here yield big returns.

  • Index queries properly, remove N+1 patterns, and profile slow queries.
  • Use read replicas or sharding only when necessary — they add cost and operational complexity.
  • Leverage caching: CDN, reverse proxies (Varnish), application-level caches, or managed caches like ElastiCache. Cache invalidation matters — aim for high hit rates before adding more cache capacity.
  • Automate on/off schedules for non-production environments

    Development and staging environments get left running 24/7. I automate schedules to save costs without slowing teams.

  • Turn off dev boxes and clusters nights and weekends with cloud scheduler tools or simple scripts.
  • Provide “start environment” buttons for developers via Slack bots or self-service UIs so productivity isn't impacted.
  • Implement tagging, budgets, and alerts

    Cost governance prevents surprises.

  • Enforce resource tagging (team, project, environment) at creation time — use policies to make tags mandatory.
  • Set budgets and alerts for teams. Trigger Slack or email notifications when spend approaches thresholds.
  • Run regular cost reviews with engineering and product stakeholders so cost becomes part of the roadmap conversations.
  • Leverage reserved instances and savings plans carefully

    Reserved instances (RIs) and savings plans can reduce compute cost if your baseline usage is predictable.

  • Buy RIs for steady-state workloads; use savings plans for flexibility across instance families.
  • Don’t overcommit. Use partial-year commitments when you expect growth or migration.
  • Make performance-efficient code a priority

    Sometimes the best savings come from algorithmic improvements.

  • Profile code for hotspots, memory bloat, and unnecessary network calls.
  • Choose more efficient libraries and reduce synchronous blocking where async pipelines or batching will do.
  • Small CPU or latency improvements can downscale instance sizes or reduce replicas, multiplying savings.
  • Table: Action, Typical Cost Impact, Performance Risk

    Action Typical Cost Impact Performance Risk
    Rightsize instances 10–40% Low if measured
    Use spot/preemptible 60–90% for compute Medium (interruptions)
    Storage lifecycle policies 10–70% depending on data Low (access delay for archive)
    Move assets to CDN Variable; reduces egress Low
    Turn off dev environments 5–25% overall Low (requires developer workflow)

    Make these changes with incremental rollouts and performance SLAs in place. Start with low-risk, high-impact items (rightsizing, lifecycle policies, turning off unused resources), then layer in more structural changes (architecture refactors, spot fleets, committed use discounts).

    Finally, keep cost optimisation ongoing. Cloud is not a “set and forget” expense. I schedule a lightweight cost review each sprint and a deeper audit quarterly. When teams treat cost as a continuous engineering problem, you get sustainable savings without sacrificing the performance your users expect.

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