On Fri, 16 Sep 2005, NeilBrown wrote:
TESTERS WANTED!! SEE BELOW... This patch changes the behaviour of raid5 when it gets a read error. Instead of just failing the device, it tried to find out what should have been there, and writes it over the bad block. For some media-errors, this has a reasonable chance of fixing the error. If the write succeeds, and a subsequent read succeeds as well, raid5 decided the address is OK and conitnues. I have tested this using the 'faulty' md personality, but it would be really good to test it with real disks that have real errors. If anyone has such drives in a cupboard (or even in a computer) and would be willing to give this a try, I would really appreciate it.
I have been trying for the last couple of weeks on a batch of drives[1] that are known to now and then pop up such errors, but I've so far only managed to find two drives with real, permanent, failure modes. I don't know if that's just because I haven't been looking hard enough, or that the disks have started to behave though.
On the other hand, it does seem stable, I still have all my [test] data. It managed to properly fail the broken disk and restripe onto a hot spare, but I have no good observations on fixable media errors.
/Mattias Wadenstein [1]: 3 4-drive raid5s with a hot spare each - 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
