Hello. I've a raid1 array (composed of 4 drives, so it is a 4-fold copy of data), and one of the drives has an unreadable (bad) sector in the partition belonging to this array. When I run md 'repair' action, it hits the error place, the kernel clearly returns an error, but md does not do anything with it. For example: Oct 21 18:43:55 mother kernel: [190018.073098] md: requested-resync of RAID array md1 Oct 21 18:43:55 mother kernel: [190018.093910] md: minimum _guaranteed_ speed: 1000 KB/sec/disk. Oct 21 18:43:55 mother kernel: [190018.114765] md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for requested-resync. Oct 21 18:43:55 mother kernel: [190018.136459] md: using 128k window, over a total of 2096064k. Oct 21 18:45:11 mother kernel: [190094.091974] ata6.00: exception Emask 0x0 SAct 0xf SErr 0x0 action 0x0 Oct 21 18:45:11 mother kernel: [190094.114093] ata6.00: irq_stat 0x40000008 Oct 21 18:45:11 mother kernel: [190094.135906] ata6.00: failed command: READ FPDMA QUEUED Oct 21 18:45:11 mother kernel: [190094.157710] ata6.00: cmd 60/00:00:00:3b:3e/04:00:00:00:00/40 tag 0 ncq 524288 in Oct 21 18:45:11 mother kernel: [190094.157710] res 41/40:00:29:3e:3e/00:00:00:00:00/40 Emask 0x409 (media error) <F> Oct 21 18:45:11 mother kernel: [190094.202315] ata6.00: status: { DRDY ERR } Oct 21 18:45:11 mother kernel: [190094.224517] ata6.00: error: { UNC } Oct 21 18:45:11 mother kernel: [190094.248920] ata6.00: configured for UDMA/133 Oct 21 18:45:11 mother kernel: [190094.271003] sd 5:0:0:0: [sdc] Unhandled sense code Oct 21 18:45:11 mother kernel: [190094.293044] sd 5:0:0:0: [sdc] Oct 21 18:45:11 mother kernel: [190094.314654] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE Oct 21 18:45:11 mother kernel: [190094.336483] sd 5:0:0:0: [sdc] Oct 21 18:45:11 mother kernel: [190094.357966] Sense Key : Medium Error [current] [descriptor] Oct 21 18:45:11 mother kernel: [190094.379808] Descriptor sense data with sense descriptors (in hex): Oct 21 18:45:11 mother kernel: [190094.402024] 72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00 Oct 21 18:45:11 mother kernel: [190094.424502] 00 3e 3e 29 Oct 21 18:45:11 mother kernel: [190094.446338] sd 5:0:0:0: [sdc] Oct 21 18:45:11 mother kernel: [190094.467995] Add. Sense: Unrecovered read error - auto reallocate failed Oct 21 18:45:11 mother kernel: [190094.490075] sd 5:0:0:0: [sdc] CDB: Oct 21 18:45:11 mother kernel: [190094.511870] Read(10): 28 00 00 3e 3b 00 00 04 00 00 Oct 21 18:45:11 mother kernel: [190094.533829] end_request: I/O error, dev sdc, sector 4079145 Oct 21 18:45:11 mother kernel: [190094.555800] ata6: EH complete Oct 21 18:45:22 mother kernel: [190105.602687] md: md1: requested-resync done. There's no indication that raid code tried to re-write the bad spot, and the bad block remains bad in the drive, so next read (direct from the drive) return the same I/O error with the same kernel messages. Shouldn't `repair' action re-write the problem place? This is kernel 3.10.15. Thank you! /mjt -- 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