On Mon, 27 Apr 2015 08:37:59 +0200 (CEST) Jean-Baptiste Thomas <cau2jeaf1honoq@xxxxxxxxxxx> wrote: > I'm looking for a way to get MD to operate in a mode in which > reading a sector from a RAID-1 device would not succeed until it > got matching data from at least two components. > > Recent experience[1] suggests that a transient problem in one > disk can completely hose a four way RAID-1 array, which is > otherwise supposed to still be fine after a triple total > failure. I'm hoping that a paranoid mode would have prevented > that. > > If there is such a thing, PLEASE tell me. If not, please tell me > so I don't waste any more time looking for it. No, there is no such thing. There "should" be no circumstance which would make it worth while. A drive may well report an error, but it should *never* report incorrect data as though it were correct. That is horribly broken. The cost of running in a "safe" mode would be high, and the likely benefit extremely low. So it is unlikely that anyone would use it for long. So implementing it seems rather pointless. That said: if someone were to provide an implementation I would certainly consider reviewing it and adding it to md. NeilBrown > > [1] "Massive RAID-1 desync" > http://www.spinics.net/lists/raid/msg48681.html > http://marc.info/?l=linux-raid&m=143003812706563&w=2 > -- > 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
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