On 02/02/18 10:41, David Brown wrote: > Using bad block lists and then doing a higher level scrub should > certainly work, and is a good general solution as it means you don't > need direct interaction between the layers (just the normal top-down > processing of layered block devices). The disadvantage is that there > may be quite a delay between the raid1 rebuild and the next full re-read > of the entire raid5 array - all you really need is a single read at the > higher level to trigger the fixup. This would be a perfect use case of my "full parity reads" mode ... at the moment, raid just reads sufficient disks to return the requested data, but I proposed a mode where it read the full stripe, did the parity checks, and either returned a read error (2-disk raid-1, raid-5) or corrected the stripe (raid-6) if things didn't add up. Okay, it would knacker performance a bit, but where you've got a nested raid like this, you switch it on, run a read on the filesystem ( tar / --no-follow > /dev/null sort of thing), and it would sort out integrity all the way down the stack. Cheers, Wol -- 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
