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Data Retention
No commands or config file changes needed — NfSen's data retention is set from the GUI. Expire old data by age, cap it by disk size, or use both for a safe two-tier approach.
Set retention from the Web UI
- Log in to the Web UI (
http://<YOUR_IP>:8070/). - Click Profile Admin in the top menu.
- In the live profile row, click Edit.
- Set Expire (how long to keep data) and Max size (hard disk cap), then Save.
The nfsend daemon applies it automatically within a few minutes — no restart needed, and it covers every router.
Expire vs Max size
| Field | What it does | Example |
|---|---|---|
| Expire | Max age of data to keep — deletes the oldest whole 5-minute files once they are older than this value. | 3d = keep 3 days |
| Max size | Max disk size of the profile's flow data — deletes oldest files until under the cap. | 44G = never exceed 44 GB |
Expire alone can still fill the disk on heavy traffic (it ignores file size). Max size guarantees it never does — on heavy traffic it just keeps less history. Setting both is the recommended approach. Only the oldest whole 5-minute files are ever removed; the file currently being written is never touched, and collection never stops.
Set retention from the command line
The GUI writes to the same per-profile config, so you can set it with one command instead — useful for scripting:
| Command | Effect |
|---|---|
nfsen --modify-profile live expire=30d maxsize=15G | 30 days of history, max 15 GB of flow data |
NfSen 1.3.6p1 retention note
live profile). The global %expire / timelimit keys only exist in newer NfSen (1.3.7+). And $profiletimout in nfsen.conf is not retention — it is just the profile refresh timeout (default 60 s) and frees no disk space.Storage planning
Raw flow files are the fastest-growing part of the stack. Watch disk usage after the first busy collection window and choose retention from observed volume. A good rule for a 20 GB disk: expire=30d maxsize=15G.