What happens if we copy neo4j's data folder while the server is running? If my neo4j server is running and I copy the data folder using copy/rsync folder, what are the chances of data corruption?
The copied store might be corrupted, but also might be recoverable.

There's a good reason neo4j has a backup tool: this method is not safe.

If you need to snapshot the file system, cleanly shut down the DB first.