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I've just had the hard disk on my server replaced.

It was part of a RAID 1 array. The sdb1 partition keeps failing every few hours now.

# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multi                                                                                                 path] [faulty]
md1 : active raid1 sdb1[2](F) sda1[0]
      463216576 blocks [2/1] [U_]

md3 : active raid1 sdb3[1] sda3[0]
      20970432 blocks [2/2] [UU]


# mdadm -D /dev/md1
        Version : 0.90
  Creation Time : Tue Dec 25 15:04:23 2012
     Raid Level : raid1
     Array Size : 463216576 (441.76 GiB 474.33 GB)
  Used Dev Size : 463216576 (441.76 GiB 474.33 GB)
   Raid Devices : 2
  Total Devices : 2
Preferred Minor : 1
    Persistence : Superblock is persistent

    Update Time : Wed Sep 25 14:30:49 2013
          State : clean, degraded
 Active Devices : 1
Working Devices : 1
 Failed Devices : 1
  Spare Devices : 0

           UUID : 6ac92849:bf49a597:a4d2adc2:26fd5302
         Events : 0.5728035

    Number   Major   Minor   RaidDevice State
       0       8        1        0      active sync   /dev/sda1
       1       0        0        1      removed

       2       8       17        -      faulty spare   /dev/sdb1

Is the newly replaced hard disk failing?

I ran smartctl, but I'm not an expert on interpreting the results:

# smartctl -a /dev/sdb
smartctl 5.43 2012-06-30 r3573 [x86_64-linux-3.10.9-xxxx-std-ipv6-64] (local build)
Copyright (C) 2002-12 by Bruce Allen, http://smartmontools.sourceforge.net

Device Model:     TOSHIBA DT01ACA050
Serial Number:    535DN5SNS
LU WWN Device Id: 5 000039 ff6d3d7bb
Firmware Version: MS1OA750
User Capacity:    500,107,862,016 bytes [500 GB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Device is:        Not in smartctl database [for details use: -P showall]
ATA Version is:   8
ATA Standard is:  ATA-8-ACS revision 4
Local Time is:    Wed Sep 25 14:28:36 2013 CEST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

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:                ( 4934) seconds.
Offline data collection
capabilities:                    (0x5b) SMART execute Offline immediate.
                                        Auto Offline data collection on/off support.
                                        Suspend Offline collection upon new
                                        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:              (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:
  1 Raw_Read_Error_Rate     0x000b   100   100   016    Pre-fail  Always       -       0
  2 Throughput_Performance  0x0005   136   136   054    Pre-fail  Offline      -       91
  3 Spin_Up_Time            0x0007   100   100   024    Pre-fail  Always       -       0
  4 Start_Stop_Count        0x0012   100   100   000    Old_age   Always       -       1
  5 Reallocated_Sector_Ct   0x0033   100   100   005    Pre-fail  Always       -       87
  7 Seek_Error_Rate         0x000b   100   100   067    Pre-fail  Always       -       0
  8 Seek_Time_Performance   0x0005   115   115   020    Pre-fail  Offline      -       34
  9 Power_On_Hours          0x0012   100   100   000    Old_age   Always       -       45
 10 Spin_Retry_Count        0x0013   100   100   060    Pre-fail  Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       1
192 Power-Off_Retract_Count 0x0032   100   100   000    Old_age   Always       -       333
193 Load_Cycle_Count        0x0012   100   100   000    Old_age   Always       -       333
194 Temperature_Celsius     0x0002   206   206   000    Old_age   Always       -       29 (Min/Max 24/32)
196 Reallocated_Event_Count 0x0032   100   100   000    Old_age   Always       -       154
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   200   000    Old_age   Always       -       0

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
    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.

Would appreciate some feedback on the results?


An engineer has looked at my logs and found the following:

ata2.00: exception Emask 0x0 SAct 0x9 SErr 0x0 action 0x6 frozen
ata2.00: failed command: WRITE FPDMA QUEUED
ata2.00: cmd 61/80:00:80:19:1f/00:00:33:00:00/40 tag 0 ncq
65536 out
     res 40/00:01:09:4f:c2/00:00:00:00:00/00 Emask 0x4
ata2.00: status: { DRDY }
ata2.00: failed command: WRITE FPDMA QUEUED
ata2.00: cmd 61/00:18:80:15:1f/04:00:33:00:00/40 tag 3 ncq
524288 out
     res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4
ata2.00: status: { DRDY }
ata2: hard resetting link
ata2: link is slow to respond, please be patient (ready=0)
ata2: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
ata2.00: configured for UDMA/133
ata2.00: device reported invalid CHS sector 0 sd 1:0:0:0: [sdb] Unhandled error code sd 1:0:0:0: [sdb]  

He wants to replace the SATA connector. Is it possible for a faulty connector to cause bad sectors on a drive? Or could a bad SATA connector be causing failures in reading sectors which then get marked as bad?

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Newly replaced doesn't mean much. What it does mean is that you can send it back for a warranty replacement. :P –  Nathan C Sep 25 '13 at 13:43
The answer to "Is my hard disk failing" is always "yes." :) –  Ryan Ries Sep 25 '13 at 14:33
@RyanRies Nope. Could be everything. Kernel, FS-Bug, Something betweet CPU und Drive, controller of the drive, parts of the drive, .. ;) But this one is probably just a refurbished, failing drive. @ Elijah Paul was this drive a warranty replacement drive? –  MKzero Sep 25 '13 at 15:48
@MKzero yes, it was a warranty replacement. The engineer has now run a smartctl self-test. Both an extended one and short one. Both have come back with no errors. Could this mean it's the 'faulty' SATA connector causing sectors to be marked as bad? –  Elijah Paul Sep 25 '13 at 18:31
@ElijahPaul I'm not sure if faulty SATA connectors could be responsible for this as to my knowledge much of the bad sector logic is in the drives controller nowadays, but I've also heard lots of strange stories of what faulty SATA connectors are capable of(though I've personally never had a broken connector..). You could try the connector exchange, then run a benchmark and if there's still errors get a replacement for the replacement. –  MKzero Sep 25 '13 at 19:15
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1 Answer

5 Reallocated_Sector_Ct  0x0033 100  100  005  Pre-fail  Always   -   87 <<<===

This is generally the count of how many bad sectors have already been added to the grown defects list that the drive keeps track of internally. NOTE: modern hard drives only remap sectors when a write occurs, so there will be a lot of cases where this attribute's raw value is 0 but the drive has numerous bad sectors pending reallocation (Current_Pending_Sector counter). When a write occurs to a bad sector, the drive will add the sector to its internal "G-List" and swap out the sector with a spare from a pool of factory-defined sectors set aside just for this purpose. If this number is more than 0, your drive has begun its downward spiral of failure, and you may have already lost data (depending on whether the drive was able to read all of the data before reallocating it or not).

196 Reallocated_Event_Count 0x0032 100 100 000  Old_age   Always  -   154 <<<===

This is generally the count of all remap attempts by the drive (both successful and unsuccessful). This may differ from the Reallocated_Sector_Ct - it will usually be higher. Watch this attribute as well.

Watch the aforementioned counters how fast they are growing. In my opinion, it's really worth replacing this drive as this one seems to be dying.

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