Reference
Workload estimation notes
A sequence for keeping a rough estimate visible, checkable, and tied to a design question.
Estimate in this order
- Clarify the workload: users, user journeys, request types, geography, daily volume, growth, and known traffic bursts.
- Separate reads and writes. Make clear whether one user action causes one request or several.
- Convert daily totals to average rates:
requests per day ÷ 86,400 seconds per day. - Estimate a stated peak:
average rate × scenario peak factor. Explain the interval and why that factor is plausible for this exercise. - Estimate retained data:
records per day × bytes per record × retention days. State whether the result is raw logical data or includes indexes, replicas, backups, and headroom. - Estimate transfer:
requests per second × average payload bytes. Keep inbound and outbound directions separate; multiply bytes per second by 8 to get bits per second. - Check whether a reasonable range changes a decision. If it does, call out the sensitivity rather than presenting a false-precision point estimate.
Keep the labels Write units beside the numbers. “170” is not useful; “about 170 read requests/second during a major on-sale” can be checked and challenged.
The arithmetic is only a model of the assumptions you wrote down. Real production choices need observed workload data, product targets, and service measurements.
Units
- 1 day = 86,400 seconds.
- 1 decimal GB = 1,000,000,000 bytes; 1 decimal MB = 1,000,000 bytes.
- 1 byte = 8 bits.
- Label decimal or binary conversions and keep the same convention through a calculation.
For related terms, see the glossary. For the learning exercise and its fictional inputs, see Workload estimation.