Position Log

Persistent station position history across restarts

By default, graywolf keeps station positions in memory only — a restart clears the live map. The position log feature writes station data to a separate SQLite database so the map is populated immediately after a restart. Positions are retained for 30 days and automatically pruned.

Enabling the Position Log

Open Settings → Position Log in the web UI, toggle Enable persistent position log, and optionally change the database path. Click Save. The change takes effect immediately — no restart required.

The database file is created automatically if it does not exist. This is important for RAM disk setups where the file disappears on every reboot.

Raspberry Pi & SD Card Considerations

SD cards have a limited number of write cycles. The position log writes to SQLite every time a new station packet is decoded — typically a few times per minute on a 1200 baud channel, but potentially more on busy frequencies or when connected to APRS-IS. Over weeks and months, this can shorten the life of an SD card.

Use a RAM disk

The simplest solution is to store the history database on a tmpfs (RAM disk). Raspberry Pi OS mounts /tmp as tmpfs by default. You can verify this:

df -h /tmp
# Look for "tmpfs" in the Filesystem column

# Or:
mount | grep /tmp

If /tmp is not a tmpfs, you can add one to /etc/fstab:

tmpfs /tmp tmpfs defaults,noatime,size=64M 0 0

Then reboot or run sudo mount -a.

Configure the database path

In the web UI under Settings → Position Log, set the database path to:

/tmp/graywolf-history.db

Alternatively, if graywolf runs as a systemd service, you can set the path via a unit override so it takes effect before the web UI is available:

sudo systemctl edit graywolf

This opens an override file. Add:

[Service]
Environment="GRAYWOLF_HISTORY_DB=/tmp/graywolf-history.db"

Then restart: sudo systemctl restart graywolf.

What happens on reboot?

With a RAM disk, the history database is lost on every reboot. This is expected and harmless — graywolf recreates the database automatically on startup. The map simply starts empty and fills in as stations are heard. On an active frequency the map is typically well-populated within a few minutes.