# Archiving

When archiving is enabled through the relevant pref (`toolkit.telemetry.archive.enabled`), pings submitted to `TelemetryController` are also stored locally in the user profile directory, in `<profile-dir>/datareporting/archived`.

To allow for cheaper lookup of archived pings, storage follows a specific naming scheme for both the directory and the ping file name: `<YYYY-MM>/<timestamp>.<UUID>.<type>.jsonlz4`.

- `<YYYY-MM>` - The subdirectory name, generated from the ping creation date.
- `<timestamp>` - Timestamp of the ping creation date.
- `<UUID>` - The ping identifier.
- `<type>` - The ping type.

Archived data can be viewed on `about:telemetry`.

## Cleanup

Archived pings are not kept around forever.
After startup of Firefox and initialization of Telemetry, the archive is cleaned up if necessary.

- Old ping data is removed by month if it is older than 60 days.
- If the total size of the archive exceeds the quota of 120 MB, pings are removed to reduce the size of the archive again.
