Hello Linux SW RAID maintainers; I am a software engineer at Stratus Technologies in Maynard, MA. I am running into an issue using the /sysfs "repair" functionality. kernel version: 2.6.18-87.el5 (RHEL5, update 2) I have a 2 member RAID level 1 set consisting of 2 SAS drives on an Adaptec aic94xx HBA. I built the raid set using the following command: mdadm -C /dev/md7 -size=5000000 -b internal -n2 -l1 /dev/sdb /dev/sde I inject a medium error onto one of the disks using sg_write_long: sg_write_long -lba=2000 -xfer_len=580 /dev/sdb I then execute: echo repair > /sys/block/md7/md/sync_action I have done some testing and I have found that if the lba is on a 4K byte aligned boundary (e.g. -lba=2000), the repair succeeds as expected. However, if the lba is "not" on a 4K byte aligned boundary (e.g. -lba=2001), the medium error is detected, but the disk gets removed from the raid set. The medium error is not repaired. The following messages appear in /var/log/messages: May 12 13:46:24 leeloo kernel: md: syncing RAID array md7 May 12 13:46:24 leeloo kernel: md: minimum _guaranteed_ reconstruction speed: 1000 KB/sec/disc. May 12 13:46:24 leeloo kernel: md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for reconstruction. May 12 13:46:24 leeloo kernel: md: using 128k window, over a total of 5000000 blocks. May 12 13:46:33 leeloo kernel: sd 0:0:1:0: SCSI error: return code = x08000002 May 12 13:46:33 leeloo kernel: sdh: Current: sense key: Medium Error May 12 13:46:33 leeloo kernel: Add. Sense: Unrecovered read error May 12 13:46:33 leeloo kernel: May 12 13:46:33 leeloo kernel: Info fld=0x7d1 May 12 13:46:33 leeloo kernel: end_request: I/O error, dev sdh, sector 2001 May 12 13:46:39 leeloo kernel: sd 0:0:1:0: SCSI error: return code = 0x00050000 May 12 13:46:39 leeloo kernel: end_request: I/O error, dev sdh, sector 1920 May 12 13:46:39 leeloo kernel: raid1: Disk failure on sdh, disabling device. May 12 13:46:39 leeloo kernel: Operation continuing on 1 devices May 12 13:46:39 leeloo kernel: md: md7: sync done I originally thought this was a low level driver issue. However, this is also reproducible on parallel scsi and Fibre Channel configurations. I have also tried this on the latest kernel with the same results. I can provide any other info necessary. Because this appears to be a 4K byte alignment (cache block size) issue, I am not sure if this is an issue in the block layer (?). Thanks; Dave -- 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
