Currently unreadable (pending) sectors

[TrevorX]

I have an issue with 8 currently unreadable sectors on disk /dev/ada8 in my FreeNAS system (hardware listed in sig). It first reared its head in early December. At the time I performed an extended offline test, which completed without errors - I was unable to zero out the pending sectors because I couldn't determine which sectors to write to. Because of that, there are still 8 uncorrectable sectors reported by SMART, which triggers a log entry every 30 minutes. Last night I performed another extended offline test which again completed without errors.

Code:

# smartctl -a /dev/ada8
smartctl 6.6 2017-11-05 r4594 [FreeBSD 11.2-STABLE amd64] (local build)
Copyright (C) 2002-17, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:     HGST Deskstar NAS
Device Model:     HGST HDN726060ALE610
LU WWN Device Id: 5 000cca 242c23aba
Firmware Version: APGNT517
User Capacity:    6,001,175,126,016 bytes [6.00 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    7200 rpm
Form Factor:      3.5 inches
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ACS-2, ATA8-ACS T13/1699-D revision 4
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is:    Sun Feb  3 13:27:47 2019 AWST
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:  (0x82) Offline data collection activity
                                        was completed without error.
                                        Auto Offline Data Collection: Enabled.
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:                (  113) seconds.
Offline data collection
capabilities:                    (0x5b) SMART execute Offline immediate.
                                        Auto Offline data collection on/off support.
                                        Suspend Offline collection upon new
                                        command.
                                        Offline surface scan supported.
                                        Self-test supported.
                                        No 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:        ( 780) 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: 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     0x000b   100   100   016    Pre-fail  Always       -       0
  2 Throughput_Performance  0x0005   137   137   054    Pre-fail  Offline      -       104
  3 Spin_Up_Time            0x0007   132   132   024    Pre-fail  Always       -       497 (Average 501)
  4 Start_Stop_Count        0x0012   100   100   000    Old_age   Always       -       105
  5 Reallocated_Sector_Ct   0x0033   100   100   005    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x000b   100   100   067    Pre-fail  Always       -       0
  8 Seek_Time_Performance   0x0005   136   136   020    Pre-fail  Offline      -       16
  9 Power_On_Hours          0x0012   096   096   000    Old_age   Always       -       33293
 10 Spin_Retry_Count        0x0013   100   100   060    Pre-fail  Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       97
192 Power-Off_Retract_Count 0x0032   048   048   000    Old_age   Always       -       63339
193 Load_Cycle_Count        0x0012   048   048   000    Old_age   Always       -       63339
194 Temperature_Celsius     0x0002   146   146   000    Old_age   Always       -       41 (Min/Max 22/60)
196 Reallocated_Event_Count 0x0032   100   100   000    Old_age   Always       -       0
197 Current_Pending_Sector  0x0022   100   100   000    Old_age   Always       -       8
198 Offline_Uncorrectable   0x0008   100   100   000    Old_age   Offline      -       0
199 UDMA_CRC_Error_Count    0x000a   200   200   000    Old_age   Always       -       0

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%     33285         -
# 2  Short offline       Completed without error       00%     33135         -
# 3  Short offline       Completed without error       00%     33134         -
# 4  Short offline       Completed without error       00%     33133         -
# 5  Short offline       Completed without error       00%     33132         -
# 6  Short offline       Completed without error       00%     33131         -
# 7  Short offline       Completed without error       00%     33130         -
# 8  Short offline       Completed without error       00%     33129         -
# 9  Short offline       Completed without error       00%     33128         -
#10  Short offline       Completed without error       00%     33127         -
#11  Short offline       Completed without error       00%     33126         -
#12  Short offline       Completed without error       00%     33125         -
#13  Short offline       Completed without error       00%     33124         -
#14  Short offline       Completed without error       00%     33123         -
#15  Short offline       Completed without error       00%     33122         -
#16  Short offline       Completed without error       00%     33121         -
#17  Short offline       Completed without error       00%     33120         -
#18  Short offline       Completed without error       00%     33119         -
#19  Short offline       Completed without error       00%     33118         -
#20  Short offline       Completed without error       00%     33117         -
#21  Short offline       Completed without error       00%     33116         -

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.

Is there a way to determine these sectors if the extended test isn't finding them? Obviously I could always pull the disk from the NAS and manually write to every single sector (forcing the drive firmware to flag those sectors and ignore them in the future, which clears the error), but that degrades the array, takes ages to rebuild and isn't exactly elegant - fixing it in-place would be highly preferable.

Thanks,

Trevor

 

[Chris Moore]

Is there a way to determine these sectors if the extended test isn't finding them? Obviously I could always pull the disk from the NAS and manually write to every single sector (forcing the drive firmware to flag those sectors and ignore them in the future, which clears the error), but that degrades the array, takes ages to rebuild and isn't exactly elegant - fixing it in-place would be highly preferable.

You would need to offline the drive, even if you don't take it out of the chassis, so the array will be degraded. It has two parity drives (RAIDz2) so even with one drive out you still have a parity drive. I have the same type of pool and I have been in this situation, what I have done was to pull the drive out and test it in another system. Just be prepared to replace it with a spare drive because it is possible that instead of correcting anything, it may show up more bad sectors. Sometimes, they can pass the long test and still have bad sectors.

Have you seen these scripts, might be helpful:

Github repository for FreeNAS scripts, including disk burnin
https://forums.freenas.org/index.ph...for-freenas-scripts-including-disk-burnin.28/

 

[Johnnie Black]

If's the extended SMART test doesn't fail then the pending sectors are "false positives", you can just ignore them, but a full disk write, with dd for example, will usually clear them.

 

[shane.prince]

Hi Johnnie i ran the smart test and the following Errors Appear
SMART Self-test log structure revision number 1
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error
# 1 Extended offline Completed: read failure 90% 18600 14862472
# 2 Extended offline Completed: read failure 90% 18595 14862472

My Zpool is also in a degraded state

 

[Johnnie Black]

Hi Johnnie i ran the smart test and the following Errors Appear

That's a different issue, my reply is about a disk that passes the extended test with pending sectors, your disk should be replaced.

 

[Chris Moore]

My Zpool is also in a degraded state

When you are posting a list of formatted text like that, please use code tags to preserve the formatting:

Doesn't this look much more readable?

Code:

SMART Self-test log structure revision number 1
Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 1  Extended offline    Completed: read failure       90%     18600         14862472
# 2  Extended offline    Completed: read failure       90%     18595         14862472

PS. Your drive is absolutely bad and needs to be replaced.