[smartmontools-support] Extended test doesn't catch CurrentPendingSector and OfflineUncorrectableSector errors

Dipanjan Das mail.dipanjan.das at gmail.com
Mon Jul 12 07:54:39 CEST 2021


Hi Christian,

On Sun, 11 Jul 2021 at 09:28, Christian Franke <Christian.Franke at t-online.de>
wrote:

>
> Some recent drives support the "Pending Defects log". Try 'smartctl -l
> defects'. This is included in 'smartctl -x' but not in '-a'.
>

Unfortunately, I guess this drive is too old to have the support for
pending defect log information. '-x' switch didn't help either.



> After such a read scan, some of the bad LBAs should appear in the "SMART
> (Extended Comprehensive) Error Log."
>

How do I print out this "Extended Comprehensive" error log? Is it the same
'-x' switch you are referring to?


I often use GNU ddrescue (https://www.gnu.org/software/ddrescue/) for
> read scans. It writes a map file of good/bad/non-tried byte ranges. This
> allows to interrupt the scan at any time and resume it later. There is
> also an option to limit the read rate.
> See the Bad Blocks HOWTO for a real world use case:
>
> https://www.smartmontools.org/wiki/BadBlockHowto#RecoveringamostlyunreadablesectorofaNotebookHDD


I ran ''ddrescue" on the whole disk. But, the result is confusing. The
"read errors" field contains 1, but the generated map file doesn't contain
any bad sectors (status column with '-' character). I am including both the
ddrescue output, the map file, and the relevant part from the 'smartctl -x'
output so that someone can shed some light. I am specifically curious to
find out 1 Current_Pending_Sector, 6 Offline_Uncorrectable, and the LBA(s)
marked by the extended self-test. Also, I am not being able to add up why
ddrescue reports one read error, but that is not reflected in the map file.
I expected the read error to match with the LBA_of_first_error field of
smartctl self-test.

=============
ddrescue output
=============
# ddrescue --ask --verbose --binary-prefixes --idirect --force /dev/sdc
/dev/null disk.map
GNU ddrescue 1.22
About to copy 1863 GiBytes
from '/dev/sdc' [UNKNOWN] (2000398934016)
  to '/dev/null' (0)
Proceed (y/N)? y
    Starting positions: infile = 0 B,  outfile = 0 B
    Copy block size: 128 sectors       Initial skip size: 39168 sectors
Sector size: 512 Bytes

     ipos:   1852 GiB, non-trimmed:        0 B,  current rate:   22528 B/s
     opos:   1852 GiB, non-scraped:        0 B,  average rate: 79108 KiB/s
non-tried:        0 B,  bad-sector:        0 B,    error rate:       0 B/s
  rescued:   1863 GiB,   bad areas:        0,        run time:  6h 51m 33s
pct rescued:  100.00%, read errors:        1,  remaining time:         n/a
                              time since last successful read:         n/a
Finished


============
ddrescue map
============
# cat disk.map
# Mapfile. Created by GNU ddrescue version 1.22
# Command line: ddrescue --ask --verbose --binary-prefixes --idirect
--force /dev/sdc /dev/null disk.map
# Start time:   2021-07-11 15:40:45
# Current time: 2021-07-11 22:32:18
# Finished
# current_pos  current_status  current_pass
0x1CF0266FE00     +               1
#      pos        size  status
0x00000000  0x1D1C1116000  +


============
smartctl -x
============
SMART Attributes Data Structure revision number: 16


Vendor Specific SMART Attributes with Thresholds:


ID# ATTRIBUTE_NAME          FLAGS    VALUE WORST THRESH FAIL RAW_VALUE


  1 Raw_Read_Error_Rate     POSR-K   200   200   051    -    4


  3 Spin_Up_Time            POS--K   152   152   021    -    9375


  4 Start_Stop_Count        -O--CK   100   100   000    -    49


  5 Reallocated_Sector_Ct   PO--CK   200   200   140    -    0


  7 Seek_Error_Rate         -OSR-K   200   200   000    -    0


  9 Power_On_Hours          -O--CK   026   026   000    -    54390


 10 Spin_Retry_Count        -O--CK   100   253   000    -    0


 11 Calibration_Retry_Count -O--CK   100   253   000    -    0


 12 Power_Cycle_Count       -O--CK   100   100   000    -    49


192 Power-Off_Retract_Count -O--CK   200   200   000    -    38


193 Load_Cycle_Count        -O--CK   200   200   000    -    10


194 Temperature_Celsius     -O---K   122   100   000    -    30


196 Reallocated_Event_Count -O--CK   200   200   000    -    0


197 Current_Pending_Sector  -O--CK   200   200   000    -    1


198 Offline_Uncorrectable   ----CK   200   200   000    -    6


199 UDMA_CRC_Error_Count    -O--CK   200   200   000    -    0


200 Multi_Zone_Error_Rate   ---R--   200   200   000    -    7

************************************************************************

SMART Extended Self-test Log Version: 1 (1 sectors)
Num  Test_Description    Status                  Remaining  LifeTime(hours)
 LBA_of_first_error
# 1  Selective offline   Completed: read failure       90%     54367
  3884004178
# 2  Selective offline   Completed without error       00%     54367
  -
# 3  Selective offline   Completed: read failure       70%     54367
  3884004178
# 4  Selective offline   Completed: read failure       90%     54367
  3884004178
# 5  Extended offline    Aborted by host               70%     54367
  -
# 6  Extended offline    Completed: read failure       90%     54268
  3884004178
# 7  Extended offline    Completed without error       00%     54206
  -
# 8  Extended offline    Completed without error       00%     54199
  -
# 9  Extended offline    Completed: read failure       90%     54190
  3884004178
#10  Short offline       Completed without error       00%     54189
  -
#11  Extended offline    Completed without error       00%     53801
  -
#12  Short captive       Completed without error       00%      1530
  -
1 of 5 failed self-tests are outdated by newer successful extended offline
self-test # 7

SMART Selective self-test log data structure revision number 1
 SPAN     MIN_LBA     MAX_LBA  CURRENT_TEST_STATUS
    1  3884004178  3884004178  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.



-- 

Thanks & Regards,
Dipanjan
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