# Logging

> Mina daemon log files, levels, formats, and export options.

Canonical URL: https://docs.minaprotocol.com/node-operators/validator-node/logging

## Log files

Mina logs are stored in `~/.mina-config/`:

| File | Description | Size limit | Rotation |
|--|--|--|--|
| `mina.log` | Main daemon logs | 10 MiB | 50 files (`mina.log.0` .. `mina.log.50`) |
| `mina-best-tip.log` | Best tip logs (useful for hard fork analysis) | 5 MiB | 1 file |
| `mina-prover.log` | Prover memory usage and batch sizes | 128 MiB | 1 file |
| `mina-verifier.log` | Verifier memory usage and batch sizes | 128 MiB | 1 file |

## Following logs

Depending on how you started the daemon:

```sh
# Docker
docker logs --follow mina-node

# Systemd
journalctl --user -u mina -n 1000 -f

# Direct
tail -f ~/.mina-config/mina.log
```

## Log levels

The Mina daemon supports the following log levels, from most to least verbose:

1. Spam
2. Trace
3. Debug
4. **Info** (default for stdout)
5. Warn
6. Error
7. Fatal

Setting a level filters out all messages below it. For example, `Info` shows only Info, Warn, Error, and Fatal messages.

## Log format

By default, logs are output as plain text. When `-log-json` is enabled, logs use the following JSON structure:

```json
{
  "timestamp": "2020-12-23 21:25:04.616526Z",
  "level": "Error",
  "source": {
    "module": "Transition_router",
    "location": "File \"src/lib/transition_router/transition_router.ml\", line 231, characters 12-24"
  },
  "message": "Failed to find any peers during initialization (crashing because this is not a seed node)",
  "metadata": {
    "host": "1.1.1.2",
    "peer_id": "12D3KooWGQSPgo7ypy9717D3Vgz2RHaqB2ndDRHEFcAfJDAv284q",
    "pid": 12,
    "port": 8302
  }
}
```

## Daemon logging options

Set these flags when starting the daemon:

| Flag | Default | Description |
|--|--|--|
| `-log-level` | Info | Log level for stdout |
| `-file-log-level` | Trace | Log level for log files |
| `-log-json` | off | Output logs as JSON instead of plain text |
| `-log-block-creation` | true | Log steps for including transactions and SNARK work in a block |
| `-log-received-blocks` | false | Log blocks received from peers |
| `-log-snark-work-gossip` | false | Log snark-pool diffs received from peers |
| `-log-txn-pool-gossip` | false | Log transaction-pool diffs received from peers |
| `-log-precomputed-blocks` | false | Include precomputed blocks in logs |

## Exporting logs

### From a running node

```sh
mina client export-logs -tarfile <FILENAME>
```

Compresses available logs into a `.tar.gz` archive in `~/.mina-config/exported_logs/`. The `-tarfile` flag is optional and defaults to the current date-time.

Logs can also be exported via GraphQL using the `exportLogs` [mutation](/node-developers/graphql-api#mutations).

### From a stopped node

```sh
mina client export-local-logs -tarfile <FILENAME>
```

Same behavior, but works without a running daemon.

## Crash reports

If the daemon crashes, it generates a crash report in `~/.mina-config/`. Only the latest report is retained, named with the crash date-time.

A crash report may contain:

| File | Description |
|--|--|
| `crash_summary.json` | System info, version, and final log output |
| `mina_status.json` | Output of `mina client status` at time of crash |
| `mina_short.log` | Last 4 MB of `mina.log` |
| `registered_mask.dot` | Latest ledger visualization |
| `frontier.dot` | Latest frontier visualization |
| `daemon.json` | Daemon configuration file |

You can upload crash reports and exported logs directly to a [GitHub issue](https://github.com/MinaProtocol/mina/issues) to help with debugging.