WD MyBook Hacks - S.M.A.R.T.

There was something that bothered me quite a lot: while the MyBook seems to have smartmontools preinstalled, I was not able to read SMART data from the hard disk:

~#:smartctl -a /dev/sda

smartctl version 5.38 [arm-unknown-linux-gnu] Copyright (C) 2002-8 Bruce Allen
Home page is http://smartmontools.sourceforge.net/

Device: WDC      WDC WD10EADS-00L Version: 01.0
Serial number:      WD-WCAU4C518954
Device type: disk
Local Time is: Wed Dec 30 16:23:35 2009 CET
Device does not support SMART

Error Counter logging not supported

[GLTSD (Global Logging Target Save Disable) set. Enable Save with '-S on']
Device does not support Self Test logging

This is strange because 3.5" SATA drives supposed to possess SMART capability. After reading the smartmontools wiki through I came up with the solution:

 ~#:smartctl -d sat -a /dev/sda

an additional "-d sat" parameter is necessary for proper operation. I note however that "-d ata" works as well. In the output we have the table that should look like something like this:

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
  1 Raw_Read_Error_Rate     0x002f   200   200   051    Pre-fail  Always       -       0
  3 Spin_Up_Time            0x0027   157   156   021    Pre-fail  Always       -       7116
  4 Start_Stop_Count        0x0032   100   100   000    Old_age   Always       -       53
  5 Reallocated_Sector_Ct   0x0033   200   200   140    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x002e   100   253   000    Old_age   Always       -       0
  9 Power_On_Hours          0x0032   100   100   000    Old_age   Always       -       171
 10 Spin_Retry_Count        0x0032   100   253   000    Old_age   Always       -       0
 11 Calibration_Retry_Count 0x0032   100   253   000    Old_age   Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       11
192 Power-Off_Retract_Count 0x0032   200   200   000    Old_age   Always       -       4
193 Load_Cycle_Count        0x0032   200   200   000    Old_age   Always       -       53
194 Temperature_Celsius     0x0022   111   100   000    Old_age   Always       -       39
196 Reallocated_Event_Count 0x0032   200   200   000    Old_age   Always       -       0
197 Current_Pending_Sector  0x0032   200   200   000    Old_age   Always       -       0
198 Offline_Uncorrectable   0x0030   100   253   000    Old_age   Offline      -       0
199 UDMA_CRC_Error_Count    0x0032   200   200   000    Old_age   Always       -       0
200 Multi_Zone_Error_Rate   0x0008   100   253   000    Old_age   Offline      -       0

SMART Error Log Version: 1
No Errors Logged

For detailed explanation of the parameters above I suggest reading the corresponding Wikipedia article.