On Jan 27, 2013, at 12:26 PM, Wolfgang Denk <wd@xxxxxxx> wrote: > I have seen "mismatch_cnt is not 0" warnings in the past, but that has > always been with RAID 1 arrays, and with relatively small numbers on > /sys/block/md*/md/mismatch_cnt; my understanding was that this was not > actually critical. Well, you have a block on each drive that's supposed to be identical, and if there's a mismatch that means they're not identical and it's ambiguous which one is correct. So if the data on the drives is unimportant to retrieve correctly, then I guess it's not a critical error. > > However, after updating to Fedora 18, I get this message from all > updated > systems that have RAID 6 arrays, and with _huge_ numbers of > mismatch_cnt, like that: > > fter updating to Fedora 18, I get this message from all updated > systems that have RAID 6 arrays, and with _huge_ numbers of > mismatch_cnt, like that: > Bad paste. No messages provided. > This is with mdadm v3.2.6 (mdadm-3.2.6-7.fc18.x86_64); except for the > huge values of mismatch_cnt, I see no other indications for errors on > the disk drives, RAID arrays or the file systems on top of these. > > Is this some known (and hopefully harmless), issue, or must I worry > about our data? It means there's a mismatch between parity and data. One of them is wrong, maybe both if there are many errors. So yeah I'd say it sounds like a problem. What's the smartctl -a look like for all drives? I imagine one or more have bad sectors, ECC errors, or UDMA/CRD errors. Chris Murphy -- 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
