3 ms·
> The problem is not “the disk lost power during a write”, the problem is “I performed a write, the disk acknowledged the write, some time later it lost power”.
by geocar 5y ago
> The problem is not “the disk lost power during a write”, the problem is “I performed a write, the disk acknowledged the write, some time later it lost power”.
I don't think this is right.
There are a lot of things that can happen after the "disk" acknowledged the write that are a lot more common than a power failure (especially in a machine with batteries!) that fsync() does nothing about, so a system that gets its reliability from fsync() cannot in practice offer any more data persistence guarantees than one that doesn't.
- masklinn 5y ago> I don't think this is right. You can think what you want, the entire thing started from marcan (re)discovering that fsync() on macos only flushes from FS to disk but does not require any guarantee of the disk. > There are a lot of things that can happen after the "disk" acknowledged the write that are a lot more common than a power failure Like what, putting a bullet through the SSD? > especially in a machine with batteries! Not every machine has a battery. Not every SSD is internal and hooked onto that battery. > a system that gets its reliability from fsync() cannot in practice offer any more data persistence guarantees than one that doesn't. So your point of view is what, reliability nihilism where data does not exist and death comes to us all?