[baruz]

Is there a performance hit for f_fullfsync?

[mananaysiempre]

Yes, that’s why those systems can cheat on benchmarks by defaulting to half-arsed fsync() in the first place.

[londons_explore]

Half arsed fsync is all I want.

I am happy to lose 5 or 10 seconds of data in a power failure. However I'm not okay with a file becoming so corrupted that it is unmountable when the power recovers.

Half arsed fsync provides exactly that - and considering you get way more performance this seems like a good tradeoff.