[smartmontools-support] I'd like to fix read failure issue on Mac OS X

[Kimio M. <xa...@ap...>]

Hello list members,

I've got an error on one of my external hdd.  smartctl -a outputs like following: 

$ smartctl -A /dev/disk5
smartctl 6.3 2014-07-26 r3976 [x86_64-apple-darwin13.3.0] (local build)
Copyright (C) 2002-14, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF READ SMART DATA SECTION ===
SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
[SNIP]
196 Reallocated_Event_Count 0x0032   100   100   000    Old_age   Always       -       17
197 Current_Pending_Sector  0x0022   100   100   000    Old_age   Always       -       1
198 Offline_Uncorrectable   0x0008   100   100   000    Old_age   Offline      -       0
199 UDMA_CRC_Error_Count    0x000a   200   200   000    Old_age   Always       -       0
223 Load_Retry_Count        0x000a   100   100   000    Old_age   Always       -       0


Since 197 Current_Pending_Sector indicates 1, I tried short test and log test.  The result is the following: 

$ smartctl -l selftest /dev/disk5
smartctl 6.3 2014-07-26 r3976 [x86_64-apple-darwin13.3.0] (local build)
Copyright (C) 2002-14, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF READ SMART DATA SECTION ===
SMART Self-test log structure revision number 1
Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 1  Short offline       Completed: read failure       50%     11263         976783240
# 2  Extended offline    Completed without error       00%     11263         -


And part of smartctl -a /dev/disk5 result is the following: 

SMART Error Log Version: 1
[SNIP]
Error 107 occurred at disk power-on lifetime: 8945 hours (372 days + 17 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 f7 b1 8f 43 42  Error: UNC 247 sectors at LBA = 0x02438fb1 = 37982129


Referring http://www.smartmontools.org/browser/trunk/www/badblockhowto.xml, I tried to find out place of bad sector using Mac OS X built-in fdisk command: 

$ sudo fdisk /dev/disk5
Password:
Disk: /dev/disk5	geometry: 60801/255/63 [976773168 sectors]
Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE 1023 254  63 - 1023 254  63 [         1 -  976773167] <Unknown ID>
 2: 00    0   0   0 -    0   0   0 [         0 -          0] unused      
 3: 00    0   0   0 -    0   0   0 [         0 -          0] unused      
 4: 00    0   0   0 -    0   0   0 [         0 -          0] unused      


Here, I got contradiction.  The LBA provided by short test is bigger than fdisk's sector size.  Also, with smratctl -a command, I got different LBA from short test result.

Even though long test passed, short test fails always.  So I am a bit worry about it.  My request is how to fix read failure in Mac OS X.

I'm very appreciate someone help me!


// Miya