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On Sun, 20 Apr 2003 17:40:29 +0100 (BST) John Bradford <john@grabjohn.com> wrote: > > > Fault tolerance in a filesystem layer means in practical terms > > > that you are guessing what a filesystem should look like, for the > > > disk doesn't answer that question anymore. IMHO you don't want > > > that to be done automagically, for it might go right sometimes, > > > but also might trash everything on RW filesystems. > > > > Let me clarify again: I don't want fancy stuff inside the filesystem that > > magically knows something about right-or-wrong. The only _very small_ > > enhancement I would like to see is: driver tells fs there is an error while > > writing a certain block => fs tries writing the same data onto another > > block. That's it, no magic, no RAID stuff. Very simple. > > That doesn't belong in the filesystem. > > Imagine you have ten blocks free, and you allocate data to all of them > in the filesystem. The write goes to cache, and succeeds. > > 30 seconds later, the write cache is flushed, and an error is reported > back from the device. And where's the problem? Your case: Immediate failure. Disk error. My case: Immediate failure. Disk error (no space left for replacement) There's no difference. Thing is: If there are 11 blocks free and not ten, then you fail and I succeed (if there's one bad block). You loose data, I don't. Regards, Stephan - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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