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I got a new drive and I'm confused if smartctl detects bad sectors or not. Both short and extended self-tests completed without error. But the Error Log indicates Uncorrectable error in data for 96 sectors.

Here's the smartctl output:

smartctl 5.41 2011-06-09 r3365 [i686-linux-3.2.0-52-generic] (local build)
Copyright (C) 2002-11 by Bruce Allen, http://smartmontools.sourceforge.net

=== START OF INFORMATION SECTION ===
Model Family:     Hitachi Deskstar T7K500
Device Model:     Hitachi HDT725025VLA380
Serial Number:    VFL104R73X993Z
LU WWN Device Id: 5 000cca 316f723ca
Firmware Version: V5DOA73A
User Capacity:    250,059,350,016 bytes [250 GB]
Sector Size:      512 bytes logical/physical
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   7
ATA Standard is:  ATA/ATAPI-7 T13 1532D revision 1
Local Time is:    Wed Feb  5 19:19:29 2014 UTC
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:  (0x80) Offline data collection activity
                    was never started.
                    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:        ( 4949) 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:    (   1) minutes.
Extended self-test routine
recommended polling time:    (  83) minutes.
SCT capabilities:          (0x003f) 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   100   100   050    Pre-fail  Offline      -       0
  3 Spin_Up_Time            0x0007   110   110   024    Pre-fail  Always       -       338 (Average 340)
  4 Start_Stop_Count        0x0012   100   100   000    Old_age   Always       -       1838
  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   100   100   020    Pre-fail  Offline      -       0
  9 Power_On_Hours          0x0012   099   099   000    Old_age   Always       -       11746
 10 Spin_Retry_Count        0x0013   100   100   060    Pre-fail  Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       1822
192 Power-Off_Retract_Count 0x0032   099   099   000    Old_age   Always       -       2103
193 Load_Cycle_Count        0x0012   099   099   000    Old_age   Always       -       2103
194 Temperature_Celsius     0x0002   162   162   000    Old_age   Always       -       37 (Min/Max 12/48)
196 Reallocated_Event_Count 0x0032   100   100   000    Old_age   Always       -       0
197 Current_Pending_Sector  0x0022   100   100   000    Old_age   Always       -       0
198 Offline_Uncorrectable   0x0008   100   100   000    Old_age   Offline      -       0
199 UDMA_CRC_Error_Count    0x000a   200   253   000    Old_age   Always       -       0

SMART Error Log Version: 1
ATA Error Count: 27 (device log contains only the most recent five errors)
    CR = Command Register [HEX]
    FR = Features Register [HEX]
    SC = Sector Count Register [HEX]
    SN = Sector Number Register [HEX]
    CL = Cylinder Low Register [HEX]
    CH = Cylinder High Register [HEX]
    DH = Device/Head Register [HEX]
    DC = Device Command Register [HEX]
    ER = Error register [HEX]
    ST = Status register [HEX]
Powered_Up_Time is measured from power on, and printed as
DDd+hh:mm:SS.sss where DD=days, hh=hours, mm=minutes,
SS=sec, and sss=millisec. It "wraps" after 49.710 days.

Error 27 occurred at disk power-on lifetime: 11706 hours (487 days + 18 hours)
  When the command that caused the error occurred, the device was active or idle.

  After command completion occurred, registers were:
  ER ST SC SN CL CH DH
  -- -- -- -- -- -- --
  40 51 60 e4 33 e7 47  Error: UNC 96 sectors at LBA = 0x07e733e4 = 132592612

  Commands leading to the command that caused the error were:
  CR FR SC SN CL CH DH DC   Powered_Up_Time  Command/Feature_Name
  -- -- -- -- -- -- -- --  ----------------  --------------------
  25 03 80 c4 33 e7 40 00      02:28:22.700  READ DMA EXT
  25 03 01 00 00 00 40 00      02:28:22.200  READ DMA EXT
  25 03 01 00 00 00 40 00      02:28:22.200  READ DMA EXT
  25 03 01 00 00 00 40 00      02:28:22.200  READ DMA EXT
  ef 03 46 c4 33 e7 00 00      02:28:22.200  SET FEATURES [Set transfer mode]

Error 26 occurred at disk power-on lifetime: 11706 hours (487 days + 18 hours)
  When the command that caused the error occurred, the device was active or idle.

  After command completion occurred, registers were:
  ER ST SC SN CL CH DH
  -- -- -- -- -- -- --
  40 51 60 e4 33 e7 47  Error: UNC 96 sectors at LBA = 0x07e733e4 = 132592612

  Commands leading to the command that caused the error were:
  CR FR SC SN CL CH DH DC   Powered_Up_Time  Command/Feature_Name
  -- -- -- -- -- -- -- --  ----------------  --------------------
  25 03 80 c4 33 e7 40 00      02:28:11.700  READ DMA EXT
  25 03 01 00 00 00 40 00      02:28:11.200  READ DMA EXT
  25 03 01 00 00 00 40 00      02:28:11.200  READ DMA EXT
  25 03 01 00 00 00 40 00      02:28:11.200  READ DMA EXT
  ef 03 46 c4 33 e7 00 00      02:28:11.200  SET FEATURES [Set transfer mode]

Error 25 occurred at disk power-on lifetime: 11706 hours (487 days + 18 hours)
  When the command that caused the error occurred, the device was active or idle.

  After command completion occurred, registers were:
  ER ST SC SN CL CH DH
  -- -- -- -- -- -- --
  40 51 60 e4 33 e7 47  Error: UNC 96 sectors at LBA = 0x07e733e4 = 132592612

  Commands leading to the command that caused the error were:
  CR FR SC SN CL CH DH DC   Powered_Up_Time  Command/Feature_Name
  -- -- -- -- -- -- -- --  ----------------  --------------------
  25 03 80 c4 33 e7 40 00      02:28:00.700  READ DMA EXT
  25 03 01 00 00 00 40 00      02:28:00.200  READ DMA EXT
  25 03 01 00 00 00 40 00      02:28:00.200  READ DMA EXT
  25 03 01 00 00 00 40 00      02:28:00.200  READ DMA EXT
  ef 03 46 c4 33 e7 00 00      02:28:00.200  SET FEATURES [Set transfer mode]

Error 24 occurred at disk power-on lifetime: 11706 hours (487 days + 18 hours)
  When the command that caused the error occurred, the device was active or idle.

  After command completion occurred, registers were:
  ER ST SC SN CL CH DH
  -- -- -- -- -- -- --
  40 51 60 e4 33 e7 47  Error: UNC 96 sectors at LBA = 0x07e733e4 = 132592612

  Commands leading to the command that caused the error were:
  CR FR SC SN CL CH DH DC   Powered_Up_Time  Command/Feature_Name
  -- -- -- -- -- -- -- --  ----------------  --------------------
  25 03 80 c4 33 e7 40 00      02:27:49.700  READ DMA EXT
  25 03 01 00 00 00 40 00      02:27:49.200  READ DMA EXT
  25 03 01 00 00 00 40 00      02:27:49.200  READ DMA EXT
  25 03 01 00 00 00 40 00      02:27:49.200  READ DMA EXT
  ef 03 46 c4 33 e7 00 00      02:27:49.200  SET FEATURES [Set transfer mode]

Error 23 occurred at disk power-on lifetime: 11706 hours (487 days + 18 hours)
  When the command that caused the error occurred, the device was active or idle.

  After command completion occurred, registers were:
  ER ST SC SN CL CH DH
  -- -- -- -- -- -- --
  40 51 60 e4 33 e7 47  Error: UNC 96 sectors at LBA = 0x07e733e4 = 132592612

  Commands leading to the command that caused the error were:
  CR FR SC SN CL CH DH DC   Powered_Up_Time  Command/Feature_Name
  -- -- -- -- -- -- -- --  ----------------  --------------------
  25 03 80 c4 33 e7 40 00      02:27:38.900  READ DMA EXT
  25 03 08 7c a8 3a 40 00      02:27:38.900  READ DMA EXT
  35 03 08 7c a8 3a 40 00      02:27:38.900  WRITE DMA EXT
  25 03 08 7c a8 3a 40 00      02:27:38.900  READ DMA EXT
  25 03 08 a4 eb 94 40 00      02:27:38.900  READ DMA EXT

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%     11746         -
# 2  Short offline       Completed without error       00%     11744         -

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.

And here's a screenshot with the Error Log: enter image description here

So what is going on? Does the drive have bad sectors or not?


UPDATE1:
Just to be sure I also used badblocks as suggested in How do you use badblocks?.

First, the non-destructive, 1h-long read-only method:

root@xubuntu:/home/xubuntu# badblocks -sv /dev/sda
Checking blocks 0 to 244198583
Checking for bad blocks (read-only test): done                                                 
Pass completed, 0 bad blocks found. (0/0/0 errors)

And then the destructive, 10h-long write method (use with care!):

root@xubuntu:/home/xubuntu# badblocks -wsv /dev/sda
Checking for bad blocks in read-write mode
From block 0 to 244198583
Testing with pattern 0xaa: done                                                 
Reading and comparing: done                                                 
Testing with pattern 0x55: done                                                 
Reading and comparing: done                                                 
Testing with pattern 0xff: done                                                 
Reading and comparing: done                                                 
Testing with pattern 0x00: done                                                 
Reading and comparing: done                                                 
Pass completed, 0 bad blocks found. (0/0/0 errors)

As suggested in the answers, it really doesn't look like there are bad sectors on this hard-drive. (Yay!)

share|improve this question
1  
All platter based drives have bad sectors, and they get marked as bad. Usually the drive knows about the sectors and doesn't report much. I suggest you download the Hitachi specific drive diagnostic utility and let that decide if you have a problem. –  bdowning Feb 5 at 21:10
    
@bdowning, no, only drives that have damage have bad sectors. –  psusi Feb 6 at 4:53

1 Answer 1

up vote 4 down vote accepted

Your disk had some problems with reading data from the surface, but it seems that the disk dealt with it. I had similar situation:

Error 29 occurred at disk power-on lifetime: 18836 hours (784 days + 20 hours)
  When the command that caused the error occurred, the device was active or idle.

  After command completion occurred, registers were:
  ER ST SC SN CL CH DH
  -- -- -- -- -- -- --
  40 51 08 00 40 37 e6  Error: UNC 8 sectors at LBA = 0x06374000 = 104284160

  Commands leading to the command that caused the error were:
  CR FR SC SN CL CH DH DC   Powered_Up_Time  Command/Feature_Name
  -- -- -- -- -- -- -- --  ----------------  --------------------
  c8 00 08 00 40 37 e6 08      03:39:32.447  READ DMA
  c8 00 08 f8 3f 37 e6 08      03:39:32.447  READ DMA
  c8 00 08 f0 3f 37 e6 08      03:39:32.447  READ DMA
  c8 00 08 e8 3f 37 e6 08      03:39:32.447  READ DMA
  c8 00 08 e0 3f 37 e6 08      03:39:32.447  READ DMA

And when I wanted to perform test, I got:

Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 7  Short offline       Completed: read failure       90%     18845         104284160

Ultimately, I managed to unblock the sectors, and after running the extended test, which scan the whole surface, I got the following result:

Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 3  Extended offline    Completed without error       00%     18858         -

If there were bad blocks, they could be observed in the table under:

  5 Reallocated_Sector_Ct   0x0033   200   200   140    Pre-fail  Always       -       0
196 Reallocated_Event_Count 0x0032   200   200   000    Old_age   Always       -       0
197 Current_Pending_Sector  0x0032   200   200   000    Old_age   Always       -       0

In your case, there's no indication of bad sectors because the extended test was performed (11746 h) after the last error occurred (11706 h). So, you can sleep peacefully. :)

As I mentioned in comments, there's two types of badblocks. Here's short info about the difference between the two:

There are two types of bad sectors — often divided into “physical” and “logical” bad sectors or “hard” and “soft” bad sectors.

A physical — or hard — bad sector is a cluster of storage on the hard drive that’s physically damaged. The hard drive’s head may have touched that part of the hard drive and damaged it, some dust may have settled on that sector and ruined it, a solid-state drive’s flash memory cell may have worn out, or the hard drive may have had other defects or wear issues that caused the sector to become physically damaged. This type of sector cannot be repaired.

A logical — or soft — bad sector is a cluster of storage on the hard drive that appears to not be working properly. The operating system may have tried to read data on the hard drive from this sector and found that the error-correcting code (ECC) didn’t match the contents of the sector, which suggests that something is wrong. These may be marked as bad sectors, but can be repaired by overwriting the drive with zeros — or, in the old days, performing a low-level format. Windows’ Disk Check tool can also repair such bad sectors.

share|improve this answer
    
Thanks! Couple of questions. "but it seems that the disk dealt with it" and "Ultimately, I managed to unblock the sectors, and after running the extended test". So do you mean that the drive indeed had bad sectors, but managed to "repair" them? –  landroni Feb 6 at 6:37
1  
There's two types of bad sectors -- logical and physical. You probably had logical ones. You can read more about the difference between the two here -- howtogeek.com/173463/… –  Mikhail Morfikov Feb 6 at 6:49
    
Makes sense, thanks! By any chance, would you mind checking out this related question on a damaged hard-drive? On that drive I get conflicting readings, and I'm not sure what to make of the logs. –  landroni Feb 6 at 7:19
    
I now read the link on bad sectors, and it is very useful to understand what is happening. It would be nice if you included it in the original answer. –  landroni Feb 6 at 10:04

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