Sample decision memo ยท September 18, 2026
The cheapest cluster is not always the right cluster.
Synthetic example. All inputs are invented. This is not a customer case study, vendor quote, measured benchmark, or delivered savings claim.
The decision
A batch workload needs 72,000 accepted classifications per day, within 18 hours. Should the team retain its eight-worker cluster, tune and shrink it, or move to elastic capacity?
Provisional recommendation: test A, the tuned four-worker cluster. It lowers modeled recurring cost while retaining enough capacity after one worker fails. The cheapest option, B, misses the delivery target under that same failure.
| Metric | Baseline | A: Tuned | B: Elastic |
|---|---|---|---|
| GPU workers | 8 | 4 | 4 |
| Compute + storage + network / month | $18,080 | $9,440 | $7,448 |
| Daily capacity after one worker fails | 126,000 | 81,000 | 58,500 |
| Meets 72,000 daily demand after that failure? | Yes | Yes | No |
| First three months, including transition | $54,240 | $34,320 | $34,344 |
What could change the answer?
- Throughput. A assumes 1,500 accepted documents per GPU-hour. At 20% below that estimate, it also misses the worker-loss target. The speed and quality assumptions need a benchmark.
- Billing. A's modeled $8,640 monthly reduction is cash savings only if the unused capacity can actually be released. A committed contract may instead yield reusable capacity.
- Resilience. B needs a longer booking window to survive the worker loss, raising modeled recurring cost to $8,744 per month. Single-worker loss is not a test of correlated node or zone failures.
- Security. Identity, tenant isolation, data access, key control, and logging must be reviewed. B also introduces a new provider and temporary data-staging boundary. None of these controls has been verified in this example.
Inspect the full work
The full memo includes billing assumptions, exclusions, transition allowances, security tradeoffs, sensitivity tests, and acceptance gates. Keep the existing cluster until the performance, security, and budget checks pass.