On Thu, 26 Nov 2009, Tamas Vincze wrote:

sda3 and sdf3 are the two members of a RAID-1.
Both disks are the same model (300GB WD velociraptors), have the same
partition layout and are on two different controllers.
This is what happened yesterday: the same sector failed on both disks at the
same time. I have a feeling that it's a bug somewhere or perhaps a power
spike? The box is on a UPS.
Running CentOS 5.4 stock kernel: 2.6.18-164.6.1
Any thoughts?

Nov 24 08:08:12 sm kernel: sd 1:0:0:0: SCSI error: return code = 0x08000002
Nov 24 08:08:12 sm kernel: sdf: Current: sense key: Medium Error
Nov 24 08:08:12 sm kernel:     Add. Sense: Record not found
Nov 24 08:08:12 sm kernel:
Nov 24 08:08:12 sm kernel: Info fld=0x1f2d8240
Nov 24 08:08:12 sm kernel: end_request: I/O error, dev sdf, sector 523076160
Nov 24 08:08:12 sm kernel: raid1: Disk failure on sdf3, disabling device.
Nov 24 08:08:12 sm kernel:      Operation continuing on 1 devices
Nov 24 08:08:12 sm kernel: sd 0:0:0:0: SCSI error: return code = 0x08000002
Nov 24 08:08:12 sm kernel: sda: Current: sense key: Medium Error
Nov 24 08:08:12 sm kernel:     Add. Sense: Record not found
Nov 24 08:08:12 sm kernel:
Nov 24 08:08:12 sm kernel: Info fld=0x1f2d8240
Nov 24 08:08:12 sm kernel: end_request: I/O error, dev sda, sector 523076160
Nov 24 08:08:12 sm kernel: RAID1 conf printout:
Nov 24 08:08:12 sm kernel:  --- wd:1 rd:2
Nov 24 08:08:12 sm kernel:  disk 0, wo:0, o:1, dev:sda3
Nov 24 08:08:12 sm kernel:  disk 1, wo:1, o:0, dev:sdf3
Nov 24 08:08:12 sm kernel: RAID1 conf printout:
Nov 24 08:08:12 sm kernel:  --- wd:1 rd:2
Nov 24 08:08:12 sm kernel:  disk 0, wo:0, o:1, dev:sda3

Disk /dev/sdf: 300.0 GB, 300069052416 bytes
255 heads, 63 sectors/track, 36481 cylinders, total 586072368 sectors
Units = sectors of 1 * 512 = 512 bytes

  Device Boot      Start         End      Blocks   Id  System
/dev/sdf1   *          63      514079      257008+  fd  Linux raid autodetect
/dev/sdf2          514080     1028159      257040   fd  Linux raid autodetect
/dev/sdf3         1028160   523076399   261024120   fd  Linux raid autodetect
/dev/sdf4       523076400   586067264    31495432+  fd  Linux raid autodetect

The failed sector is near the end of the partition.
There's LVM on top of the raid and only the first 30GB or so is allocated,
so it wasn't any filesystem that made the request to that sector.
It must have been either the LVM or raid metadata, but I'm not sure where
they are allocated.

Oh, and it continued to operate on sda3 even though that also seem to have
failed.

Hi,

Do not use velociraptors in RAID, they do not work, I have confirmed this 
finding here:
http://forums.storagereview.net/index.php?showtopic=27303

In addition, just for the sake of it I tried a RAID with Windows 7 with 
four-drives and the same problem happened.

What you are seeing is completely normal, these drives are broken for a 
RAID configuration and WD will not replace them with other models.

Justin.