On Wed, Sep 28 2016, scar wrote: > Chris Murphy wrote on 09/14/2016 08:51 PM: >> On Wed, Sep 14, 2016 at 9:42 PM, scar wrote: >> >>> 00 80 00 >>> Sep 12 08:05:34 hind kernel: [1350051.023847] end_request: critical medium >>> error, dev sdk, sector 598457896 >>> Sep 12 08:05:35 hind kernel: [1350051.385810] md/raid:md0: read error >>> corrected (8 sectors at 598455848 on sdk1) >>> Sep 12 08:05:35 hind kernel: [1350051.385826] md/raid:md0: read error >>> corrected (8 sectors at 598455856 on sdk1) >>> Sep 12 08:05:35 hind kernel: [1350051.385834] md/raid:md0: read error >>> corrected (8 sectors at 598455864 on sdk1) >>> Sep 12 08:05:35 hind kernel: [1350051.385840] md/raid:md0: read error >>> corrected (8 sectors at 598455872 on sdk1) >>> Sep 12 08:05:35 hind kernel: [1350051.385847] md/raid:md0: read error >>> corrected (8 sectors at 598455880 on sdk1) >>> Sep 12 08:05:35 hind kernel: [1350051.385853] md/raid:md0: read error >>> corrected (8 sectors at 598455888 on sdk1) >>> Sep 12 08:05:35 hind kernel: [1350051.385859] md/raid:md0: read error >>> corrected (8 sectors at 598455896 on sdk1) >>> Sep 12 08:05:35 hind kernel: [1350051.385865] md/raid:md0: read error >>> corrected (8 sectors at 598455904 on sdk1) >>> Sep 12 08:05:35 hind kernel: [1350051.385873] md/raid:md0: read error >>> corrected (8 sectors at 598455912 on sdk1) >>> Sep 12 08:05:35 hind kernel: [1350051.385880] md/raid:md0: read error >>> corrected (8 sectors at 598455920 on sdk1) >>> Sep 12 13:39:43 hind kernel: [1370087.022160] md: md0: data-check done. >>> >>> >>> so it seems to be working? although the sector reported by libata is >>> different than what md corrected >> >> Looks like it replaced the entire chunk that includes the bad sector. >> Is the chunk size 32KiB? >> > > No it is 512K, and the sector reported by libata is almost 2000 sectors > different than what mdadm reported The difference is probably the Data Offset. libata reports a sector in the device. md reports a sector in the data section of the device. NeilBrown