lots of pending sectors appear and disappear

Hello

On a new SSD from French vendor "LDLC", smart often sends an error
message at boot saying
"Device: /dev/sda [SAT], 262144 Currently unreadable (pending) sectors"
The number of pending sectors has been either 262144, 524288 or 786432.
Sometimes, it goes back to 0 for several days. And later it goes back up
for no obvious reason.

Smart reports 0 reallocated sectors (full output below). Smart short and
long tests report no problem. dmesg shows no problem. badblocks reports
no problem (only tested on the partition that covers 75% of the disk).

Reading the documentation, I feel like these sectors are "temporarily"
unaccessible and come back to life later? That's quite disturbing since
262144 sectors is quite a lot. Any idea how to debug this further? Is
there anything useful in the full smartctl output below?

The vendor wants me to run HD Tune Pro but obviously I don't even have
Windows and I am not even sure it would be more useful than smartctl...

Regards
Brice Goglin


smartctl 6.5 2016-01-24 r4214 [x86_64-linux-4.5.0-2-amd64] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke,
http://www.smartmontools.org

=== START OF INFORMATION SECTION ===
Device Model:     LDLC
Serial Number:    SZHYPO16010606F0146
Firmware Version: O1026A
User Capacity:    120 034 123 776 bytes [120 GB]
Sector Size:      512 bytes logical/physical
Rotation Rate:    Solid State Device
Device is:        Not in smartctl database [for details use: -P showall]
ATA Version is:   ACS-2 (minor revision not indicated)
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is:    Sat Jul  9 21:40:03 2016 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:  (0x02) Offline data collection activity
     was completed without error.
     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:   (   57) seconds.
Offline data collection
capabilities:     (0x71) SMART execute Offline immediate.
     No Auto Offline data collection support.
     Suspend Offline collection upon new
     command.
     No Offline surface scan supported.
     Self-test supported.
     Conveyance Self-test supported.
     Selective Self-test supported.
SMART capabilities:            (0x0002) Does not save 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:   (   1) minutes.
Extended self-test routine
recommended polling time:   (   1) minutes.
Conveyance self-test routine
recommended polling time:   (   1) minutes.
SCT capabilities:         (0x003d) SCT Status supported.
     SCT Error Recovery Control supported.
     SCT Feature Control supported.
     SCT Data Table supported.

SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH
TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x0000   100   100   000    Old_age  
Offline      -       0
  5 Reallocated_Sector_Ct   0x0000   100   100   000    Old_age  
Offline      -       0
  9 Power_On_Hours          0x0000   100   100   000    Old_age  
Offline      -       1803
12 Power_Cycle_Count       0x0000   100   100   000    Old_age  
Offline      -       28
160 Unknown_Attribute       0x0000   100   100   000    Old_age  
Offline      -       0
161 Unknown_Attribute       0x0000   100   100   000    Old_age  
Offline      -       99
163 Unknown_Attribute       0x0000   100   100   000    Old_age  
Offline      -       39
164 Unknown_Attribute       0x0000   100   100   000    Old_age  
Offline      -       9510
165 Unknown_Attribute       0x0000   100   100   000    Old_age  
Offline      -       27
166 Unknown_Attribute       0x0000   100   100   000    Old_age  
Offline      -       0
167 Unknown_Attribute       0x0000   100   100   000    Old_age  
Offline      -       9
168 Unknown_Attribute       0x0000   100   100   000    Old_age  
Offline      -       3000
169 Unknown_Attribute       0x0000   100   100   000    Old_age  
Offline      -       100
175 Program_Fail_Count_Chip 0x0000   100   100   000    Old_age  
Offline      -       0
176 Erase_Fail_Count_Chip   0x0000   100   100   000    Old_age  
Offline      -       0
177 Wear_Leveling_Count     0x0000   100   100   050    Old_age  
Offline      -       0
178 Used_Rsvd_Blk_Cnt_Chip  0x0000   100   100   000    Old_age  
Offline      -       0
181 Program_Fail_Cnt_Total  0x0000   100   100   000    Old_age  
Offline      -       0
182 Erase_Fail_Count_Total  0x0000   100   100   000    Old_age  
Offline      -       0
192 Power-Off_Retract_Count 0x0000   100   100   000    Old_age  
Offline      -       2
194 Temperature_Celsius     0x0000   100   100   000    Old_age  
Offline      -       40
195 Hardware_ECC_Recovered  0x0000   100   100   000    Old_age  
Offline      -       19693
196 Reallocated_Event_Count 0x0000   100   100   016    Old_age  
Offline      -       0
197 Current_Pending_Sector  0x0000   100   100   000    Old_age  
Offline      -       0
198 Offline_Uncorrectable   0x0000   100   100   000    Old_age  
Offline      -       0
199 UDMA_CRC_Error_Count    0x0000   100   100   050    Old_age  
Offline      -       0
232 Available_Reservd_Space 0x0000   100   100   000    Old_age  
Offline      -       100
241 Total_LBAs_Written      0x0000   100   100   000    Old_age  
Offline      -       22065
242 Total_LBAs_Read         0x0000   100   100   000    Old_age  
Offline      -       13709
245 Unknown_Attribute       0x0000   100   100   000    Old_age  
Offline      -       38040

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  Extended offline    Completed without error      
00%        10         -
# 2  Short offline       Completed without error       00%        
4         -

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
    7        0    65535  Read_scanning was completed without error
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.


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