NetFlow Storage Calculator
Size NetFlow collector storage and export bandwidth from flow rate, sampling and retention.
Inputs
Retained Storage Required
2 TiB
Raw Volume Per Day
89 GiB
Flow Records Per Day
1,728,000,000
Export Bandwidth
8.80Mbit/s
Retained Storage Required
1.945TB
Step by step
Values used
Flows per second = 20,000 flows/s; Bytes per flow record = 55 bytes; Sampling rate (1 in N) = 1 N; Retention period = 90 days; Compression ratio = 4 ×
NetFlow Storage
storage = flows/s ÷ sampling × 86400 × record bytes × retention ÷ compression, with NetFlow v9 records running 40–70 bytes each.
Exporter to collector bandwidth
export bandwidth = exported flows/s × record bytes × 8
Retained Storage Required
= 2,138,400,000,000
Raw Volume Per Day
= 95,040,000,000
Flow Records Per Day
= 1,728,000,000
Export Bandwidth
= 8.80 Mbit/s
Retained Storage Required
= 1.945 TB
How it works
Flow export volume is the flow rate times the record size; sampling divides the rate directly, which is why 1-in-1000 sampling is the standard way to make high-rate interfaces affordable to monitor. Retention and compression scale the stored figure. Flow data grows faster than any other telemetry — a busy edge router at 20,000 flows per second produces around 95 GB a day unsampled, which decides whether you need sampling or a bigger array.
Formulas
NetFlow Storage
storage = flows/s ÷ sampling × 86400 × record bytes × retention ÷ compression, with NetFlow v9 records running 40–70 bytes each.
- record bytes
- Size of one exported flow record — 40 to 70 bytes for NetFlow v9
- sampling
- 1-in-N packet or flow sampling divisor
- compression
- Collector compression of stored records
Exporter to collector bandwidth
export bandwidth = exported flows/s × record bytes × 8
- exported flows/s
- Flow rate after sampling
Frequently Asked Questions
How is NetFlow Storage calculated?
storage = flows/s ÷ sampling × 86400 × record bytes × retention ÷ compression, with NetFlow v9 records running 40–70 bytes each. Flow export volume is the flow rate times the record size; sampling divides the rate directly, which is why 1-in-1000 sampling is the standard way to make high-rate interfaces affordable to monitor. Retention and compression scale the stored figure.
Why does NetFlow Storage matter?
Flow data grows faster than any other telemetry — a busy edge router at 20,000 flows per second produces around 95 GB a day unsampled, which decides whether you need sampling or a bigger array.
What values do I need to enter?
This calculator takes 5 inputs: Flows per second, Bytes per flow record, Sampling rate (1 in N), Retention period, Compression ratio. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.
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