How to interpret following S.M.A.R.T values: “ATA Error Count”, Offline_Uncorrectable?

I have a harddisk (Western Digital) with increased ATA Error Count, I have searched through different posts on different forums, some of them state the HDD is ■■■■, others say the connection (SATA-cable) has problems.

Smart tests itself didn’t show problems - raw values are (as far as I can say) good.

Any ideas? I’m also unsure what a worst value of 253 in “Offline_uncorrectable” and Multi_Zone_Error_Rate could mean. As the raw value is 0 there shouldn’t be bad sectors.

Thanks in advance!

=== START OF INFORMATION SECTION ===
Model Family:     Western Digital Red
Device Model:     WDC WD20EFRX-68AX9N0
Serial Number:    XXXXXXXXXXX
LU WWN Device Id: XXXXXXXXXXX
Firmware Version: 80.00A80
User Capacity:    2.000.398.934.016 bytes [2,00 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ACS-2 (minor revision not indicated)
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Wed Aug  7 08:59:50 2019 CEST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status:  (0x00)	Offline data collection activity
					was never started.
					Auto Offline Data Collection: Disabled.
Self-test execution status:      (   0)	The previous self-test routine completed
					without error or no self-test has ever 
					been run.
Total time to complete Offline 
data collection: 		(26400) seconds.
Offline data collection
capabilities: 			 (0x7b) SMART execute Offline immediate.
					Auto Offline data collection on/off support.
					Suspend Offline collection upon new
					command.
					Offline surface scan supported.
					Self-test supported.
					Conveyance Self-test supported.
					Selective Self-test supported.
SMART capabilities:            (0x0003)	Saves SMART data before entering
					power-saving mode.
					Supports SMART auto save timer.
Error logging capability:        (0x01)	Error logging supported.
					General Purpose Logging supported.
Short self-test routine 
recommended polling time: 	 (   2) minutes.
Extended self-test routine
recommended polling time: 	 ( 266) minutes.
Conveyance self-test routine
recommended polling time: 	 (   5) minutes.
SCT capabilities: 	       (0x70bd)	SCT Status supported.
					SCT Error Recovery Control supported.
					SCT Feature Control supported.
					SCT Data Table supported.

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   174   158   021    Pre-fail  Always       -       6300
  4 Start_Stop_Count        0x0032   100   100   000    Old_age   Always       -       129
  5 Reallocated_Sector_Ct   0x0033   200   200   140    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x002e   200   200   000    Old_age   Always       -       0
  9 Power_On_Hours          0x0032   098   098   000    Old_age   Always       -       2082
 10 Spin_Retry_Count        0x0032   100   100   000    Old_age   Always       -       0
 11 Calibration_Retry_Count 0x0032   100   100   000    Old_age   Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       129
192 Power-Off_Retract_Count 0x0032   200   200   000    Old_age   Always       -       15
193 Load_Cycle_Count        0x0032   200   200   000    Old_age   Always       -       113
194 Temperature_Celsius     0x0022   124   106   000    Old_age   Always       -       26
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
ATA Error Count: 40878 (device log contains only the most recent five errors)
	CR = Command Register [HEX]
	FR = Features Register [HEX]
	SC = Sector Count Register [HEX]
	SN = Sector Number Register [HEX]
	CL = Cylinder Low Register [HEX]
	CH = Cylinder High Register [HEX]
	DH = Device/Head Register [HEX]
	DC = Device Command Register [HEX]
	ER = Error register [HEX]
	ST = Status register [HEX]
Powered_Up_Time is measured from power on, and printed as
DDd+hh:mm:SS.sss where DD=days, hh=hours, mm=minutes,
SS=sec, and sss=millisec. It "wraps" after 49.710 days.

Error 40878 occurred at disk power-on lifetime: 2054 hours (85 days + 14 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
  -- -- -- -- -- -- --
  04 61 f2 00 00 00 40

  Commands leading to the command that caused the error were:
  CR FR SC SN CL CH DH DC   Powered_Up_Time  Command/Feature_Name
  -- -- -- -- -- -- -- --  ----------------  --------------------
  e3 00 f2 00 00 00 40 00      22:51:53.472  IDLE
  ef 10 02 00 00 00 a0 00      22:51:52.394  SET FEATURES [Enable SATA feature]
  ec 00 00 00 00 00 a0 00      22:51:52.392  IDENTIFY DEVICE
  ef 03 46 00 00 00 a0 00      22:51:52.392  SET FEATURES [Set transfer mode]
  ef 10 02 00 00 00 a0 00      22:51:52.392  SET FEATURES [Enable SATA feature]
  
  ... 4 similar errors are shown here ...

Hello Cyber1000,

You could refer to the following article for more information:
https://support-en.wd.com/app/answers/detail/a_id/12163

Thanks for your help!

That article only explains how to install tools for Mac and Windows to get SMART data and not how to interpret them. I must admit my output is SMART-data outputted from linux, since I don’t have a Windows/Mac-device capable of inserting devices. I’ve started the smart-tests on linux, as they are solely executed on the drive itself, the result should be the same.

  1. I’ve found so far that values of 253 are (very) good ones, so Offline_Uncorrectable and Multi_Zone_Error_Rate should be ok.
  2. ATA Error Count: this is a little bit trickier. It just says communication didn’t go well to the motherboard. This may be a problem internal in disk, the SATA cable or in the motherboard/SATA-controller.

My solution:

  • Since SATA-Tests all passed (even the extended test) and SATA Attributes seem ok, I’ll have to go deeper
  • SATA tests are readonly only, I’ve found a linux tool which reads a sector, does some writingtests on that sector and then writes back the contents of the old sector: badblocks -nsv /dev/device
    (https://wiki.archlinux.org/index.php/badblocks#Comparisons_with_Other_Programs)
  • Needs more than one day on 2TB, but writing is always better than just reading when testing harddisks.
  • I’m doing this on another computer with a new SATA-cable, if the tests go well, I put the disk back in my other computer, but I’ll use a new SATA-cable.
  • If the tests reveal any problems I’ll exchange the drive

I’m just testing, so I’ll report back in some days.

For Windows an elevated command prompt can check clusters and map out any flakey ones

chkdsk /r

the /r option asks chkdsk to use the recovery of sectors and that can take a while with modern hard disks

My solution was to run an extended test with

badblocks -nsv -t 0 -t 95 -t 197 -t 255 /dev/device

This reads the content of the sector, writes pattern 0, checks for pattern 0 and writes the old content of sector. (non destructive mode)
After the whole disk is finished it does the same for pattern 95 and so on.

So as a whole 4 complete writes of the disk, lasted 4 days for 2 TB!

With the new SATA cable no changes in ATA Error Count, so I’ll use this disk. The cable seems to be broken.