mongodb hot backup
// Lock The FileSytem
// https://docs.mongodb.com/manual/reference/method/db.fsyncLock/
db.fsyncLock()
// then zip the data directory, your data directory might be different
// compressing may take a long time, so just zip it
tar -cvf ~/mongo-backup.tar /var/lib/mongodb
// Then release the filesystem lock
db.fsyncUnlock()