# unreadable (pending) sectors



## fernandel (Dec 14, 2019)

Hi!

Soon will be 1 year as I put the new SSD hard drive and last few weeks I have in /var/log/messages:


> smartd[32299]: Device: /dev/ada0, 1 Currently unreadable (pending) sectors


I did run short and long test but there are no errors. What should be wrong, please?

Thank you.


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## ralphbsz (Dec 15, 2019)

Print the output from smarctl -a for the disk. Most likely there is a defective sector that has read errors, and that's a bad (but perhaps not catastrophic) thing.
And make sure you have a good backup; the disk is likely (but not guaranteed) to fail soon.


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## fernandel (Dec 15, 2019)

ralphbsz said:


> Print the output from smarctl -a for the disk. Most likely there is a defective sector that has read errors, and that's a bad (but perhaps not catastrophic) thing.
> And make sure you have a good backup; the disk is likely (but not guaranteed) to fail soon.




```
smartctl 7.0 2018-12-30 r4883 [FreeBSD 12.1-RELEASE-p1 amd64] (local build)
Copyright (C) 2002-18, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Device Model:     Mercury Electra 3G SSD
Serial Number:    OW181126100473DEA
LU WWN Device Id: 5 888914 000000000
Firmware Version: R0522A0
User Capacity:    500,107,862,016 bytes [500 GB]
Sector Size:      512 bytes logical/physical
Rotation Rate:    Solid State Device
Form Factor:      2.5 inches
Device is:        Not in smartctl database [for details use: -P showall]
ATA Version is:   ACS-2 T13/2015-D revision 3
SATA Version is:  SATA 3.2, 3.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Sun Dec 15 05:48:44 2019 EST
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:         (  120) seconds.
Offline data collection
capabilities:              (0x11) SMART execute Offline immediate.
                    No Auto Offline data collection support.
                    Suspend Offline collection upon new
                    command.
                    No Offline surface scan supported.
                    Self-test supported.
                    No Conveyance Self-test supported.
                    No 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:      (   2) minutes.
Extended self-test routine
recommended polling time:      (  10) minutes.

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     0x0032   100   100   050    Old_age   Always       -       0
  5 Reallocated_Sector_Ct   0x0032   100   100   050    Old_age   Always       -       1
  9 Power_On_Hours          0x0032   100   100   050    Old_age   Always       -       2837
12 Power_Cycle_Count       0x0032   100   100   050    Old_age   Always       -       510
160 Unknown_Attribute       0x0032   100   100   050    Old_age   Always       -       0
161 Unknown_Attribute       0x0033   100   100   050    Pre-fail  Always       -       97
163 Unknown_Attribute       0x0032   100   100   050    Old_age   Always       -       36
164 Unknown_Attribute       0x0032   100   100   050    Old_age   Always       -       22577
165 Unknown_Attribute       0x0032   100   100   050    Old_age   Always       -       74
166 Unknown_Attribute       0x0032   100   100   050    Old_age   Always       -       2
167 Unknown_Attribute       0x0032   100   100   050    Old_age   Always       -       48
168 Unknown_Attribute       0x0032   100   100   050    Old_age   Always       -       7000
169 Unknown_Attribute       0x0032   100   100   050    Old_age   Always       -       100
175 Program_Fail_Count_Chip 0x0032   100   100   050    Old_age   Always       -       0
176 Erase_Fail_Count_Chip   0x0032   100   100   050    Old_age   Always       -       0
177 Wear_Leveling_Count     0x0032   100   100   050    Old_age   Always       -       0
178 Used_Rsvd_Blk_Cnt_Chip  0x0032   100   100   050    Old_age   Always       -       1
181 Program_Fail_Cnt_Total  0x0032   100   100   050    Old_age   Always       -       0
182 Erase_Fail_Count_Total  0x0032   100   100   050    Old_age   Always       -       0
192 Power-Off_Retract_Count 0x0032   100   100   050    Old_age   Always       -       42
194 Temperature_Celsius     0x0022   100   100   050    Old_age   Always       -       55
195 Hardware_ECC_Recovered  0x0032   100   100   050    Old_age   Always       -       202763
196 Reallocated_Event_Count 0x0032   100   100   050    Old_age   Always       -       0
197 Current_Pending_Sector  0x0032   100   100   050    Old_age   Always       -       1
198 Offline_Uncorrectable   0x0032   100   100   050    Old_age   Always       -       0
199 UDMA_CRC_Error_Count    0x0032   100   100   050    Old_age   Always       -       0
232 Available_Reservd_Space 0x0032   100   100   050    Old_age   Always       -       97
241 Total_LBAs_Written      0x0030   100   100   050    Old_age   Offline      -       192064
242 Total_LBAs_Read         0x0030   100   100   050    Old_age   Offline      -       78229
245 Unknown_Attribute       0x0032   100   100   050    Old_age   Always       -       177480

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 without error       00%      2822         -
# 2  Extended offline    Completed without error       00%      2709         -
# 3  Short offline       Completed without error       00%      2709         -
# 4  Extended offline    Completed without error       00%      2468         -
# 5  Short offline       Completed without error       00%      2365         -
# 6  Short offline       Completed without error       00%        62         -
# 7  Short offline       Completed without error       00%        11         -
# 8  Short offline       Completed without error       00%         4         -

Selective Self-tests/Logging not supported
```

I am using iMac 11,1 late 2009 and almost year ago I did change HD and I have just FreeBSD on.


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## ralphbsz (Dec 15, 2019)

Interesting. This is an SSD, and it has been used very little ... total power-on time is only ~120 days (4 months) and only 200K sectors written (that's a tiny fraction of the capacity), yet it has one pending sector (sector that had a read error and is waiting to be remapped, most likely on the next write). This is either extremely bad 

I have no idea whether a Mercury Electra is a good or a bad model. A little web research shows it to be a private-label product of a reseller named Other World Computing. It could be complete junk, it could be excellent quality, I can't tell. I would make sure you have a good backup, and see whether you can return this one under warranty.


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## fernandel (Dec 15, 2019)

ralphbsz said:


> Interesting. This is an SSD, and it has been used very little ... total power-on time is only ~120 days (4 months) and only 200K sectors written (that's a tiny fraction of the capacity), yet it has one pending sector (sector that had a read error and is waiting to be remapped, most likely on the next write). This is either extremely bad
> 
> I have no idea whether a Mercury Electra is a good or a bad model. A little web research shows it to be a private-label product of a reseller named Other World Computing. It could be complete junk, it could be excellent quality, I can't tell. I would make sure you have a good backup, and see whether you can return this one under warranty.


The drive was recommended for my iMac (it is old). I have backup and I think to buy a laptop, possible used Lenovo T470s.


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## VladiBG (Dec 15, 2019)

SMART ID 161 = 97% left from spare blocks so you have some bad cells that are replaced by the spare one.


```
Attribute 161 - Valid Spare Block Count
Contains the remaining spare block percentage
available on a solid state device. The percentage
starts at 100% and will typically decrease to 0% during use. If this attribute reaches 0%, the solid state
device becomes read-only. The raw value of this
attribute may contain the actual number of spare
blocks.
```


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## ralphbsz (Dec 15, 2019)

VladiBG said:


> SMART ID 161 = 97% left from spare blocks so you have some bad cells that are replaced by the spare one.


Yes, but he also had one sector (or cell or block or ... whatever they call it) that had an actual read error. With ECC that should *NEVER* happen. Yet it did. That could mean a variety of things. Astronomically bad luck (see footnote), buggy SSD firmware implementation, they used sketchy chips. But whatever it is, it might be systemic, and affect other sectors.

Footnote: Old saying: Bad luck in gambling, good luck in love. If you extend that to bad luck disk drives, then Fernandel will get well laid soon.


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## fernandel (Dec 15, 2019)

ralphbsz said:


> Yes, but he also had one sector (or cell or block or ... whatever they call it) that had an actual read error. With ECC that should *NEVER* happen. Yet it did. That could mean a variety of things. Astronomically bad luck (see footnote), buggy SSD firmware implementation, they used sketchy chips. But whatever it is, it might be systemic, and affect other sectors.
> 
> Footnote: Old saying: Bad luck in gambling, good luck in love. If you extend that to bad luck disk drives, then Fernandel will get well laid soon.


Fernandel is no lucky 
I try `smartctl -c`

```
smartctl 7.0 2018-12-30 r4883 [FreeBSD 12.1-RELEASE-p1 amd64] (local build)
Copyright (C) 2002-18, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Device Model:     Mercury Electra 3G SSD
Serial Number:    OW181126100473DEA
LU WWN Device Id: 5 888914 000000000
Firmware Version: R0522A0
User Capacity:    500,107,862,016 bytes [500 GB]
Sector Size:      512 bytes logical/physical
Rotation Rate:    Solid State Device
Form Factor:      2.5 inches
Device is:        Not in smartctl database [for details use: -P showall]
ATA Version is:   ACS-2 T13/2015-D revision 3
SATA Version is:  SATA 3.2, 3.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Sun Dec 15 17:25:34 2019 EST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
AAM feature is:   Unavailable
APM level is:     128 (minimum power consumption without standby)
Rd look-ahead is: Enabled
Write cache is:   Enabled
DSN feature is:   Unavailable
ATA Security is:  Disabled, frozen [SEC2]
Wt Cache Reorder: Unavailable

=== 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:         (  120) seconds.
Offline data collection
capabilities:              (0x11) SMART execute Offline immediate.
                    No Auto Offline data collection support.
                    Suspend Offline collection upon new
                    command.
                    No Offline surface scan supported.
                    Self-test supported.
                    No Conveyance Self-test supported.
                    No 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:      (   2) minutes.
Extended self-test routine
recommended polling time:      (  10) minutes.

SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAGS    VALUE WORST THRESH FAIL RAW_VALUE
  1 Raw_Read_Error_Rate     -O--CK   100   100   050    -    0
  5 Reallocated_Sector_Ct   -O--CK   100   100   050    -    1
  9 Power_On_Hours          -O--CK   100   100   050    -    2849
 12 Power_Cycle_Count       -O--CK   100   100   050    -    510
160 Unknown_Attribute       -O--CK   100   100   050    -    0
161 Unknown_Attribute       PO--CK   100   100   050    -    97
163 Unknown_Attribute       -O--CK   100   100   050    -    36
164 Unknown_Attribute       -O--CK   100   100   050    -    22591
165 Unknown_Attribute       -O--CK   100   100   050    -    74
166 Unknown_Attribute       -O--CK   100   100   050    -    2
167 Unknown_Attribute       -O--CK   100   100   050    -    48
168 Unknown_Attribute       -O--CK   100   100   050    -    7000
169 Unknown_Attribute       -O--CK   100   100   050    -    100
175 Program_Fail_Count_Chip -O--CK   100   100   050    -    0
176 Erase_Fail_Count_Chip   -O--CK   100   100   050    -    0
177 Wear_Leveling_Count     -O--CK   100   100   050    -    0
178 Used_Rsvd_Blk_Cnt_Chip  -O--CK   100   100   050    -    1
181 Program_Fail_Cnt_Total  -O--CK   100   100   050    -    0
182 Erase_Fail_Count_Total  -O--CK   100   100   050    -    0
192 Power-Off_Retract_Count -O--CK   100   100   050    -    42
194 Temperature_Celsius     -O---K   100   100   050    -    55
195 Hardware_ECC_Recovered  -O--CK   100   100   050    -    202771
196 Reallocated_Event_Count -O--CK   100   100   050    -    0
197 Current_Pending_Sector  -O--CK   100   100   050    -    1
198 Offline_Uncorrectable   -O--CK   100   100   050    -    0
199 UDMA_CRC_Error_Count    -O--CK   100   100   050    -    0
232 Available_Reservd_Space -O--CK   100   100   050    -    97
241 Total_LBAs_Written      ----CK   100   100   050    -    192194
242 Total_LBAs_Read         ----CK   100   100   050    -    78261
245 Unknown_Attribute       -O--CK   100   100   050    -    177552
                            ||||||_ K auto-keep
                            |||||__ C event count
                            ||||___ R error rate
                            |||____ S speed/performance
                            ||_____ O updated online
                            |______ P prefailure warning

General Purpose Log Directory Version 1
SMART           Log Directory Version 1 [multi-sector log support]
Address    Access  R/W   Size  Description
0x00       GPL,SL  R/O      1  Log Directory
0x01           SL  R/O      1  Summary SMART error log
0x02           SL  R/O      1  Comprehensive SMART error log
0x03       GPL     R/O      1  Ext. Comprehensive SMART error log
0x04       GPL,SL  R/O      8  Device Statistics log
0x06           SL  R/O      1  SMART self-test log
0x07       GPL     R/O      1  Extended self-test log
0x10       GPL     R/O      1  NCQ Command Error log
0x11       GPL     R/O      1  SATA Phy Event Counters log
0x30       GPL,SL  R/O      9  IDENTIFY DEVICE data log
0x80-0x9f  GPL,SL  R/W     16  Host vendor specific log
0xde       GPL     VS       8  Device vendor specific log

SMART Extended Comprehensive Error Log Version: 1 (1 sectors)
No Errors Logged

SMART Extended Self-test Log Version: 1 (1 sectors)
Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 1  Short offline       Completed without error       00%      2822         -
# 2  Extended offline    Completed without error       00%      2709         -
# 3  Short offline       Completed without error       00%      2709         -
# 4  Extended offline    Completed without error       00%      2468         -
# 5  Short offline       Completed without error       00%      2365         -
# 6  Short offline       Completed without error       00%        62         -
# 7  Short offline       Completed without error       00%        11         -
# 8  Short offline       Completed without error       00%         4         -

Selective Self-tests/Logging not supported

SCT Commands not supported

Device Statistics (GP Log 0x04)
Page  Offset Size        Value Flags Description
0x01  =====  =               =  ===  == General Statistics (rev 1) ==
0x01  0x008  4             510  ---  Lifetime Power-On Resets
0x01  0x010  4            2849  ---  Power-on Hours
0x01  0x018  6      4005745599  ---  Logical Sectors Written
0x01  0x020  6         1617473  ---  Number of Write Commands
0x01  0x028  6       833996419  ---  Logical Sectors Read
0x01  0x030  6         2103919  ---  Number of Read Commands
0x07  =====  =               =  ===  == Solid State Device Statistics (rev 1) ==
0x07  0x008  1               0  ---  Percentage Used Endurance Indicator
                                |||_ C monitored condition met
                                ||__ D supports DSN
                                |___ N normalized value

Pending Defects log (GP Log 0x0c) not supported

SATA Phy Event Counters (GP Log 0x11)
ID      Size     Value  Description
0x0001  4            0  Command failed due to ICRC error
0x0002  4            0  R_ERR response for data FIS
0x0005  4            0  R_ERR response for non-data FIS
0x000a  4            7  Device-to-host register FISes sent due to a COMRESET
```

Not much different...


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