A/B Testing Memory Requirement Calculator FAQ
Answers to common questions about estimating A/B test event storage, retention capacity, replication, inputs, and results.
This FAQ explains what the storage estimate includes, how the calculator treats its inputs, and why actual platform capacity may differ from the calculated event payload.
General storage questions
Basic questions about the purpose and scope of the calculator.
What does the A/B Testing Memory Requirement Calculator estimate?
It estimates daily event ingestion, annual replicated event storage, peak retained storage, daily event records, and average visitors per variant.
Is memory the same as storage in this calculator?
The calculator estimates persistent data storage capacity for event records, not short-term application RAM or in-memory processing capacity.
What data can count as an A/B testing event?
Examples include variant assignments, exposures, page views, clicks, conversions, revenue events, and experiment-related behavioral records.
Can this calculator be used for multiple experiments?
Yes, if the daily visitor and event inputs represent the combined activity of the active experiments being planned.
Formula and input questions
How traffic, event activity, variants, and event size affect the result.
How are daily event records calculated?
Daily event records equal average daily test visitors multiplied by tracked events per visitor.
Does the number of variants multiply the storage result?
No. The variant count is used only to show average visitors per variant. Total storage is driven by total visitors and events, not an even audience split.
What event size should I enter?
Use the average stored record size after applicable serialization, field selection, and compression. A measured sample is generally more representative than a raw payload estimate.
Why does event size have such a large effect?
Every stored event uses the specified average size, so a change in event size applies across all daily records and retained copies.
What unit does the calculator use for storage?
It reports GiB and converts using 1 GiB = 1,048,576 KB.
Retention and replication questions
How the calculator handles data lifetime and stored copies.
What is peak retained storage?
It is the estimated replicated event payload held when the chosen number of retention days has accumulated.
When are annual storage and peak retained storage equal?
They are equal in this model when retention is 365 days and the same daily rate applies throughout the year.
What does a replication factor of 2 mean?
It means the event payload is modeled as having two stored copies, so payload capacity is multiplied by two.
Does replication include backups?
No. Replication and backups are separate concepts in many systems. Backup capacity is not included unless it is reflected in a higher planning multiplier outside the calculator.
Accuracy and planning questions
How to interpret the estimate for practical capacity planning.
Why might actual storage be higher than the estimate?
Indexes, metadata, partitions, backups, logs, minimum allocation sizes, traffic peaks, and platform overhead can all increase actual capacity use.
Does the estimate allow for traffic growth?
No. It uses the average daily visitor input as constant. Growth can be evaluated by rerunning the calculator with a higher expected traffic level.
Does the calculator account for data compression?
Only if the event-size input already reflects compressed stored records. Compression is not applied separately.
Should this result be treated as an exact capacity requirement?
No. It is an event-payload estimate intended for planning. Actual requirements depend on the storage technology and operating configuration.
How is annual A/B testing storage calculated?
It multiplies daily visitors, events per visitor, and event size, converts KB to GiB, then applies 365 days and the replication factor.
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