fsync is cheaper than you think
With all the talk about the new ext4’s interactions with gconfd, kde, firefox, and others, a lot of people have been assuming fsync is expensive.
If you’re living under a rock and don’t know what’s going on, here’s the short version: Lots of programs don’t write to files reliably because (a) writing to files reliably requires some contortions, and (b) writing to files reliably is slow.
Neither of these things are true, and I wrote libreliable to prove it.
libreliable is a simple, mostly portable way to get reliable file i/o
without an fsync()-penalty after every write.
That means you have no excuse for not updating your files reliably.
The included demo should show how it works. It’s fun to watch in strace/truss.