And overkill for almost all intermediate sized installations, but a great use of their technology to meet their requirements, thanks for the link.

Of course Twitter have snowflake: https://github.com/twitter/snowflake and many other tools such as UUID[4r] - see an old discussion on HN: http://news.ycombinator.com/item?id=1396667

Of course I wanted sequential, small IDs, within a small margin of acceptable loss (if a save fails that ID is never used), that were't taking up a massive amount of space.