The only thing I can add to everyone else's replies is: VERSION IT. This will allow you to write a parser which parses all versions of your log format, whichev

The only thing I can add to everyone else's replies is: VERSION IT. This will allow you to write a parser which parses all versions of your log format, whichever such versions are – based on the version… and allow you to amend the log format at any time without worry that suddenly your old logs aren't going to be compatible with new ones. "we" use this even for Apache access log files, and it's one small thing which has helped a ton.