Overwrite uncorrectable error LBA?

[Stefan Bethke]

Smartctl is reporting an uncorrectable error for one of my disks:

=== START OF INFORMATION SECTION ===
Model Family:     Hitachi Deskstar 7K2000
Device Model:     Hitachi HDS722020ALA330
Serial Number:    JK1130YAHXN28T
LU WWN Device Id: 5 000cca 221db1d3f
Firmware Version: JKAOA28A
User Capacity:    2,000,398,934,016 bytes [2.00 TB]
Sector Size:      512 bytes logical/physical
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   8
ATA Standard is:  ATA-8-ACS revision 4
Local Time is:    Tue Jan  3 09:38:46 2012 CET
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
...
197 Current_Pending_Sector  0x0022   100   100   000    Old_age   Always       -       1
...
Error 25 occurred at disk power-on lifetime: 7362 hours (306 days + 18 hours)
  When the command that caused the error occurred, the device was active or idle.

  After command completion occurred, registers were:
  ER ST SC SN CL CH DH
  -- -- -- -- -- -- --
  40 51 68 d0 cd d0 00  Error: UNC at LBA = 0x00d0cdd0 = 13684176

  Commands leading to the command that caused the error were:
  CR FR SC SN CL CH DH DC   Powered_Up_Time  Command/Feature_Name
  -- -- -- -- -- -- -- --  ----------------  --------------------
  60 ab 60 90 d3 d0 40 00  33d+04:43:22.635  READ FPDMA QUEUED
  60 ab 58 e5 d2 d0 40 00  33d+04:43:22.634  READ FPDMA QUEUED
  60 ab 50 3a d2 d0 40 00  33d+04:43:22.634  READ FPDMA QUEUED
  60 ab 48 8f d1 d0 40 00  33d+04:43:22.634  READ FPDMA QUEUED
  60 ab 40 e4 d0 d0 40 00  33d+04:43:22.634  READ FPDMA QUEUED

I'm reading this as LBA 13684176 being the one uncorrectable error.

Since this disk is part of a ZRAID1 pool, I'd just overwrite that LBA to have the disk remap it, but I'm not sure how to address it properly: dd seemingly reads that LBA without problems?

# dd if=/dev/ada0 iseek=13684176 count=1 of=/dev/null
1+0 records in
1+0 records out
512 bytes transferred in 0.025676 secs (19941 bytes/sec)

I would have expected the disk to either take a long time or respond with an I/O error outright.  Am I looking at the right LBA?

I currently have a zpool scrub running, and I will start a long test after that just to make sure there's no further problems hiding.  Any other suggestions?


Stefan

-- 
Stefan Bethke <stb at lassitu.de>   Fon +49 151 14070811