You assume that logging has happen to disk. It does not. Look at Varnish. For every request it can log as much as 400 lines. Because the logging is done to memo

You assume that logging has happen to disk. It does not. Look at Varnish. For every request it can log as much as 400 lines. Because the logging is done to memory the cost of logging is more or less zero. And since it is a circular buffer the memory cost is fixed. Since the memory is shared and available through the filesystem the log stays around if the application crashes.