On Fri, Dec 23, 2016 at 11:56:34AM +1100, Eyal Lebedinsky wrote: > 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. "repair" should fix the data which is assumed to be wrong. It should not simply correct P+Q, but really find out which disk is not OK and fix it. > > '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 -- piergiorgio -- 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
