12

Over the course of a week, for a 3TB Seagate drive (ST3000DM001-1CH166), smartd reported a slowly increasing number of offline uncorrectable and currently unreadable (pending) sectors, then a decreasing number, until finally the count was 0 and the error condition reset. From the logs (showing only changes):

Jul  6 18:04:57 x smartd[462]: Device: /dev/sdb [SAT], 8 Currently unreadable (pending) sectors
Jul  6 18:04:58 x smartd[462]: Device: /dev/sdb [SAT], 8 Offline uncorrectable sectors
[...]
Jul  7 16:34:58 x smartd[462]: Device: /dev/sdb [SAT], 16 Currently unreadable (pending) sectors (changed +8)
Jul  7 16:34:58 x smartd[462]: Device: /dev/sdb [SAT], 16 Offline uncorrectable sectors (changed +8)
[...]
Jul 11 14:04:57 x smartd[462]: Device: /dev/sdb [SAT], 24 Currently unreadable (pending) sectors (changed +8)
Jul 11 14:04:57 x smartd[462]: Device: /dev/sdb [SAT], 24 Offline uncorrectable sectors (changed +8)
Jul 11 14:34:57 x smartd[462]: Device: /dev/sdb [SAT], 32 Currently unreadable (pending) sectors (changed +8)
Jul 11 14:34:58 x smartd[462]: Device: /dev/sdb [SAT], 32 Offline uncorrectable sectors (changed +8)
[...]
Jul 13 09:04:57 x smartd[462]: Device: /dev/sdb [SAT], 24 Currently unreadable (pending) sectors (changed -8)
Jul 13 09:04:57 x smartd[462]: Device: /dev/sdb [SAT], 24 Offline uncorrectable sectors (changed -8)
Jul 13 09:34:58 x smartd[462]: Device: /dev/sdb [SAT], 16 Currently unreadable (pending) sectors (changed -8)
Jul 13 09:34:58 x smartd[462]: Device: /dev/sdb [SAT], 16 Offline uncorrectable sectors (changed -8)
Jul 13 10:04:57 x smartd[462]: Device: /dev/sdb [SAT], 16 Currently unreadable (pending) sectors
Jul 13 10:04:57 x smartd[462]: Device: /dev/sdb [SAT], 16 Offline uncorrectable sectors
Jul 13 10:34:57 x smartd[462]: Device: /dev/sdb [SAT], No more Currently unreadable (pending) sectors, warning condition reset after 1 email
Jul 13 10:34:57 x smartd[462]: Device: /dev/sdb [SAT], No more Offline uncorrectable sectors, warning condition reset after 1 email

Furthermore, the reallocated sector count is also 0, so the sectors do not appear to have been re-mapped. Here is the complete (current) smartctl -a output for the drive:

smartctl 6.2 2013-07-26 r3841 [x86_64-linux-3.14.4-100.fc19.x86_64] (local build)
Copyright (C) 2002-13, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:     Seagate Barracuda 7200.14 (AF)
Device Model:     ST3000DM001-1CH166
Serial Number:    W1F30FK2
LU WWN Device Id: 5 000c50 06129a9a8
Firmware Version: CC27
User Capacity:    3,000,592,982,016 bytes [3.00 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    7200 rpm
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ACS-2, ACS-3 T13/2161-D revision 3b
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Wed Jul 16 11:23:08 2014 EDT

==> WARNING: A firmware update for this drive may be available,
see the following Seagate web pages:
http://knowledge.seagate.com/articles/en_US/FAQ/207931en
http://knowledge.seagate.com/articles/en_US/FAQ/223651en

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:      (   0) The previous self-test routine completed
                    without error or no self-test has ever 
                    been run.
Total time to complete Offline 
data collection:        (  584) seconds.
Offline data collection
capabilities:            (0x73) SMART execute Offline immediate.
                    Auto Offline data collection on/off 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:            (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:    (   1) minutes.
Extended self-test routine
recommended polling time:    ( 347) minutes.
Conveyance self-test routine
recommended polling time:    (   2) minutes.
SCT capabilities:          (0x3085) SCT Status supported.

SMART Attributes Data Structure revision number: 10
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x000f   115   099   006    Pre-fail  Always       -       91131424
  3 Spin_Up_Time            0x0003   094   094   000    Pre-fail  Always       -       0
  4 Start_Stop_Count        0x0032   100   100   020    Old_age   Always       -       12
  5 Reallocated_Sector_Ct   0x0033   100   100   010    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x000f   078   060   030    Pre-fail  Always       -       59138260
  9 Power_On_Hours          0x0032   094   094   000    Old_age   Always       -       5888
 10 Spin_Retry_Count        0x0013   100   100   097    Pre-fail  Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   020    Old_age   Always       -       12
183 Runtime_Bad_Block       0x0032   100   100   000    Old_age   Always       -       0
184 End-to-End_Error        0x0032   100   100   099    Old_age   Always       -       0
187 Reported_Uncorrect      0x0032   100   100   000    Old_age   Always       -       0
188 Command_Timeout         0x0032   100   100   000    Old_age   Always       -       0 0 0
189 High_Fly_Writes         0x003a   097   097   000    Old_age   Always       -       3
190 Airflow_Temperature_Cel 0x0022   053   049   045    Old_age   Always       -       47 (Min/Max 23/51)
191 G-Sense_Error_Rate      0x0032   100   100   000    Old_age   Always       -       0
192 Power-Off_Retract_Count 0x0032   100   100   000    Old_age   Always       -       10
193 Load_Cycle_Count        0x0032   096   096   000    Old_age   Always       -       8086
194 Temperature_Celsius     0x0022   047   051   000    Old_age   Always       -       47 (0 22 0 0 0)
197 Current_Pending_Sector  0x0012   100   100   000    Old_age   Always       -       0
198 Offline_Uncorrectable   0x0010   100   100   000    Old_age   Offline      -       0
199 UDMA_CRC_Error_Count    0x003e   200   200   000    Old_age   Always       -       0
240 Head_Flying_Hours       0x0000   100   253   000    Old_age   Offline      -       5703h+56m+25.808s
241 Total_LBAs_Written      0x0000   100   253   000    Old_age   Offline      -       11838196191
242 Total_LBAs_Read         0x0000   100   253   000    Old_age   Offline      -       211237637103

SMART Error Log Version: 1
No Errors Logged

SMART Self-test log structure revision number 1
No self-tests have been logged.  [To run self-tests, use: smartctl -t]


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.

I have downloaded but not yet run Seatools on the drive, but the current SMART status of the drive basically seems fine. What could cause such behavior?

UPDATE: For future readers, the drive was actually fine for a couple more months, at which point more sectors become uncorrectable/offline, and the number of reallocated sectors started increasing beyond 0, and the SMART long self-test started failing with a read error. So these messages appeared to be a useful early warning.

  • The question is: Do you trust this disk? I wouldn't and replace it ASAP. – Sven Jul 16 '14 at 15:37
  • SMART can be uh...not smart sometimes? I wouldn't trust this disk with any data. From the looks of the power-on hours, the drive's 8 months old(ish)...do you have a warranty? – Nathan C Jul 16 '14 at 15:49
  • Yes, it is under warranty. The next step according to Seagate's warranty information is to run Seatools on it. – Raman Jul 16 '14 at 16:02
  • 1
    Update: a couple of months later, the drive self-test is now failing, and reallocated sectors are increasing. I'm returning the drive for warranty replacement. – Raman Sep 22 '14 at 19:17
  • The same thing happened today with my Seagate drive. I had a read error while copying a large file, so I looked at SMART data and saw Reallocated Sector Count=8, Current Pending Sector=10, Offline Uncrorrectable=10. Then I ran a full format. After that I see Reallocated Sector Count=8, but Current Pending Sector=0 - so, if there are no pending sectors and Reallocated Sectors did not go up, this means that they were not actually bad, right? But I was shocked to see Offline Uncrorrectable=0. How Uncrorrectable sectors could go corrected after full format, that's a mystery... – JustAMartin Sep 27 '15 at 19:42
9

I've had this a few times recently with a similar Seagate ST3000DM001-1CH166 firmware CC24. You don't need Seatools, just run a long smart test:

smartctl -t long /dev/sdc

Then if smarctl shows no error you're OK for now:

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%      9912         -

If it fails then send straight back to Seagate. They replaced my last failed one in about a week.

| improve this answer | |
  • The extended offline self-test completed without error. – Raman Sep 3 '14 at 22:07
  • 4
    Update: a couple of months later, the drive self-test is now failing, and reallocated sectors are increasing. I'm returning the drive for warranty replacement. – Raman Sep 22 '14 at 19:15
  • 4
    Damn those disks! They appears to have 40% of failure rate. – Vinícius Ferrão Jun 21 '15 at 23:03
11

Current Pending Sector is just that, the number of locations the disk knows about that needs to be reallocated but haven't reallocated yet since the disk has no source for the data to be reallocated. Once you write into that location the disk will automatically reallocate the area to another place and write the new data in the new place and the current pending sector cound will decrease.

This is all perfectly fine and how the disk should operate.

You can use diskscan on Linux or HD Tune on Windows to scan the disk for the bad locations and also attempt to "fix" the locations by making the software write into them in order to attempt the reallocation immediately.

| improve this answer | |
  • 1
    Thanks but I know what "current pending sector" means. In my question, you'll see that I specifically noted that the reallocation count was still zero. Do you have any explanation for a decreasing pending sector count without a corresponding increase in reallocation count? Note all the disk tests I have run are fine and the disk is still humming along with no apparent issues. – Raman Sep 3 '14 at 22:09
  • 2
    It is possible that the disk had an unreadable sector and so there was a pending sector, when the time came to write on the location the disk can test the location and see that the write got through and so canceled the reallocation which explains that the counter went to zero but there was no added reallocations. – Baruch Even Sep 5 '14 at 11:57
  • Ok, that makes sense for Current Pending Sector. But how Offline Uncrorrectable can go from 10 to 0? Doesn't "Uncrorrectable" mean that they are gone for good and will stay offline forever? – JustAMartin Sep 27 '15 at 19:45
  • On Ubuntu, instead of installing from github, just sudo apt-get install diskscan. (I guess you're the author of both versions.) – Camille Goudeseune Apr 24 '17 at 21:01

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