smartctl 報告整體健康測試通過但測試失敗？

為什麼SMART overall-health self-assessment test result: PASSED兩次測試都失敗時顯示？

sudo smartctl -a /dev/sdc 
smartctl 6.6 2018-12-05 r4851 [x86_64-linux-4.14.98] (local build)
Copyright (C) 2002-17, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:     Western Digital AV-GP (AF)
Device Model:     WDC WD20EURS-63SPKY0
Serial Number:    WD-WMC1T2763021
LU WWN Device Id: 5 0014ee 6addb4b7c
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, 3.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Sun Feb 24 13:43:30 2019 GMT
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:      ( 117) The previous self-test completed having
                   the read element of the test failed.
Total time to complete Offline 
data collection:        (27240) 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:    ( 275) minutes.
Conveyance self-test routine
recommended polling time:    (   5) minutes.
SCT capabilities:          (0x70b5) SCT Status 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   180   179   021    Pre-fail  Always       -       5991
 4 Start_Stop_Count        0x0032   100   100   000    Old_age   Always       -       113
 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   092   092   000    Old_age   Always       -       6354
10 Spin_Retry_Count        0x0032   100   100   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       -       56
192 Power-Off_Retract_Count 0x0032   200   200   000    Old_age   Always       -       46
193 Load_Cycle_Count        0x0032   200   200   000    Old_age   Always       -       66
194 Temperature_Celsius     0x0022   122   114   000    Old_age   Always       -       28
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   200   200   000    Old_age   Offline      -       1

SMART Error Log Version: 1
No Errors Logged

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%      6354         4377408
# 2  Extended offline    Completed: read failure       90%      6354         4377408

SMART Selective self-test log data structure revision number 1
SPAN  MIN_LBA  MAX_LBA  CURRENT_TEST_STATUS
   1        0        0  Not_testing
   2        0        0  Not_testing
   3        0        0  Not_testing
   4        0        0  Not_testing
   5        0        0  Not_testing
Selective self-test flags (0x0):
 After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.

因為您的 SMART 屬性都處於良好狀態，並且有No Errors Logged.

請閱讀：ATA 驅動器自檢失敗，但 SMART 健康狀態為“通過”。這是怎麼回事？

如果驅動器未能通過自檢，但仍處於“通過”SMART 健康狀態，這通常意味著磁碟上有損壞的（不可糾正=UNC）扇區。這意味著儲存在該扇區的 ECC 數據與儲存在該扇區的使用者數據不一致，並且嘗試讀取該扇區失敗並出現 UNC 錯誤。這可能是一次性的瞬態效應：磁碟寫入扇區時突然斷電會損壞 ECC 程式碼或數據，但扇區可以正確儲存新數據。或者它可能是永久性的影響：磁介質已被一點灰塵損壞，扇區無法正確儲存新數據。

如果磁碟可以一次讀取該扇區的數據，並且損壞是永久性的，而不是暫時的，那麼磁碟韌體會將扇區標記為“壞”並分配一個備用扇區來替換它。但是，如果磁碟甚至一次都無法讀取該扇區，那麼它就不會重新分配該扇區，以期在未來的某個時間能夠從中讀取數據。**寫入不可讀（損壞）的扇區將解決問題。**如果損壞是暫時的，那麼新的一致數據將被寫入該扇區。如果損壞是永久性的，那麼寫入將強制扇區重新分配。有關如何強制該扇區重新分配（僅限 Linux）的說明，請參閱壞塊 HOWTO 。

磁碟仍然具有通過健康狀態，因為韌體沒有發現其他故障跡象，例如伺服故障。

此類磁碟通常可以通過使用磁碟製造商的“磁碟評估和修復”實用程序進行修復。注意：這可能會強制重新分配失去的扇區，從而破壞或破壞磁碟上的任何文件系統。有關通用 Linux 指令，請參閱壞塊 HOWTO。

您可以嘗試使用dd或使用某種“修復實用程序”來修復無法讀取的扇區。首先備份您的驅動器！

引用自：https://unix.stackexchange.com/questions/502693