ext4 and data consistency

> We have dozens of Debian systems running on ext3 (presumably without paranoid mode), and we have not had a single problem with a dpkg database corrupted by the file system.

No filesystem goes out and corrupts the dpkg database, but dpkg failing to properly ensure on-disk consistency might make it possible for an untimely power failure (or whatever) to trash its database. How often do you pull the plug while dpkg is running?

That's why robustness is so hard -- it's almost impossible to test. That doesn't mean it isn't important. All it takes is one power failure with just the right timing to trash a datastore. Which is, of course, the whole problem here -- it means that as users we have to rely on external signals, like how I still don't really trust MySQL, because sure, I know they have transactions now, but do I *really* trust a group who was at one point talking about how useless they are to later have the necessary mind-numbing paranoia to catch every edge case? And hey, over here there's Postgres, whose developers clearly *are* absurdly paranoid, excellent...

Or, how you don't trust ext4, even though you have no statistics on it either, because of how Ted T'so's messages came across. It's just a mystery to me how his basically sensible posts gave you (and others) this image of him as some kind of data-eating monster.