On Mon, May 8, 2017 at 2:27 PM, Anthony Youngman <antlists@xxxxxxxxxxxxxxx> wrote: > Yes you have saved a sector sparing. Note that a consumer 3TB drive can > return, on average, one error every time it's read from end to end 3 times, > and still be considered "within spec" ie "not faulty" by the manufacturer. All specs say "less than" which means it's a maximum permissible rate, not an average. We have no idea what the minimum error rate is - we being consumers. It's possible high volume users (e.g. Backblaze) have data on this by now. > And that's a *brand* *new* drive. That's why building a large array using > consumer drives is a stupid idea - 4 x 3TB drives and a *within* *spec* > array must expect to handle at least one error every scrub. The requirement for any large array is quickly abandoning reattempted reads in favor of reporting a read error. That's the main reason why consumer drives are a bad idea, is that it can hang user space waiting on the long recovery of a drive. -- Chris Murphy -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
