From time to time I get non-zero mismatch_count in the weekly scrub. The way I handle it is to run a check around the stripe (I have a background job printing the mismatch count and /proc/mdstat regularly) which should report the same count. I now drill into the fs to find which files use this area, deal with them and delete the bad ones. I then run a repair on that small area. I now found about raid6check which can actually tell me which disk holds the bad data. This is something raid6 should be able to do assuming a single error. Hoping it is one bad disk, the simple solution now is to recover the bad stripe on that disk. Will a 'repair' rewrite the bad disk or just create fresh P+Q which may just make the bad data invisible to a 'check'? I recall this being the case in the past. 'man md' still says For RAID5/RAID6 new parity blocks are written I think RAID6 can do better. TIA -- Eyal Lebedinsky (eyal@xxxxxxxxxxxxxx) -- 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
