Troubleshooting

Typical errors and solutions are described here.

Unavailable `LOCK` file

Error: IO error: While lock file /root/.local/share/gear-node/chains/staging_testnet_v2/db/full/LOCK: Resource temporarily unavailable
Solution: You seem to be running several Gear node instances. Note that only one node instance is allowed to run. You likely have configured the node as a service and then ran the second instance from the command line. You should either stop the service or don't run the Gear node from the command line.
You can see the current node processes by running the command:
```
ps aux | grep gear-node
```
If you want to break all node processes you may run:
```
pkill -sigint gear-node
```
Note that the SystemD service can't be stopped by the command above. Run instead:
```
sudo systemctl stop gear-node
```

Error: Found argument '\' which wasn't expected, or isn't valid in this context
Solution: The gear-node.service configuration file seems to be misconfigured. Some versions of SystemD do not accept the backslash character (\) as a line break. Therefore, it is better to write each of the config entry on one line.
Refer to https://wiki.gear-tech.io/node/node-as-service for properly configuring the node as a service.
Don't forget to restart the node after fixing the service configuration:
```
sudo systemctl daemon-reload
sudo systemctl restart gear-node
```

Error: Database version cannot be read from existing db_version file
Alternative error: Invalid argument: Column families not opened: ..., col2, col1, col0
Solution: The root of this problem is the lack of the disk free space. You may check the free space using the following command:
```
df -h
```
Also, you may check how many space is used by the blockchain DB:
```
du -h $HOME/.local/share/gear-node/chains/staging_testnet_v2/db/full
```
Please refer to the System Requirements to see the minimum disk space required.
You need to free more space then purge the chain:
```
sudo systemctl stop gear-node
# Provide more free space on the disk
gear-node purge-chain
sudo systemctl start gear-node
```

Error: Verification failed for block <block-id> received from peer <peer-id>
Alternative error: runtime requires function imports which are not present on the host
Solution: Update the node binary to the latest version.

Error: Failed to start gear-node.service: Unit gear-node.service is masked.
Solution: Please check: https://askubuntu.com/questions/1017311/what-is-a-masked-service