Description of my problem is quite large, so first I will give a short summary, then I will precisely describe the situation.
Short summary: manufacturer's diagnostic tools found and repaired some errors on my hard disk. As far as I understand tool's manual, these errors were bad blocks. However, smartctl (Linux tool to do SMART on hard disk) doesn't show any reallocated sectors and says that hard disk is good. First question: how is it possible? Reparation of bad blocks means reallocating sectors, right? So why don't smartctl report any reallocated sectors? Second question: I bought this disk a few months ago and I still have warranty for it. Should I demand that seller replace it for a new one or is this disk good and I could continue using it?
And now precise description:
I have Western Digital hard disk, model WDC WD5000AAKX-001CA0. Recently I noticed that sometimes my computer hangs for a few seconds (something like up to one minute). After such hangs dmesg shows errors like this:
knoppix@Microknoppix:~$ dmesg
(...)
[ 504.003363] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
[ 504.003374] ata1.00: failed command: READ DMA EXT
[ 504.003383] ata1.00: cmd 25/00:00:80:07:01/00:02:00:00:00/e0 tag 0 dma 262144 in
[ 504.003385] res 40/00:00:09:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout)
[ 504.003389] ata1.00: status: { DRDY }
[ 509.016652] ata1: link is slow to respond, please be patient (ready=0)
[ 514.030002] ata1: soft resetting link
[ 514.200386] ata1.00: configured for UDMA/133
[ 514.200420] ata1: EH complete
[ 546.003333] ata1: lost interrupt (Status 0x50)
[ 546.003364] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
[ 546.003371] ata1.00: failed command: READ DMA EXT
[ 546.003380] ata1.00: cmd 25/00:00:80:15:06/00:02:00:00:00/e0 tag 0 dma 262144 in
[ 546.003381] res 40/00:00:09:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout)
[ 546.003386] ata1.00: status: { DRDY }
[ 546.003401] ata1: soft resetting link
[ 546.181205] ata1.00: configured for UDMA/133
[ 546.181234] ata1: EH complete
However, smartctl says that "SMART overall-health self-assessment test result: PASSED" (I will paste complete output of smartctl few paragraphs later). Whenever I tried to make smartctl self test (with smartctl -t short or smartctl -t long) such tests were reported as aborted by host. So I downloaded bootable CD diagnostic tool for my hd – this one: http://support.wdc.com/product/download.asp?groupid=606&sid=2&lang=en
Using this tool first I did quick test and it showed error (unfortunately, I don't remember what was the error code). As far as I understand this tool performs just SMART quick self test (http://wdc.custhelp.com/app/answers/detail/search/1/a_id/940/c/130/p/227,295 says "QUICK TEST – performs SMART drive quick self-test to gather and verify the Data Lifeguard information contained on the drive.") Then I did extended test. As far as I understand, this extended test looks for bad sectors (http://wdc.custhelp.com/app/answers/detail/search/1/a_id/940/c/130/p/227,295 says "EXTENDED TEST – performs a Full Media Scan to detect bad sectors"). After some time the tool told that it found and repaired some errors.
Now I booted machine with knoppix and did "smartctl –all". Here is its output:
root@Microknoppix:/home/knoppix# smartctl --all /dev/sda
smartctl 5.43 2012-06-05 r3561 [i686-linux-3.4.9] (local build)
Copyright (C) 2002-12 by Bruce Allen, http://smartmontools.sourceforge.net
=== START OF INFORMATION SECTION ===
Model Family: Western Digital Caviar Blue Serial ATA
Device Model: WDC WD5000AAKX-001CA0
Serial Number: WD-WMAYUW952768
LU WWN Device Id: 5 0014ee 6ad1d9ef1
Firmware Version: 15.01H15
User Capacity: 500,107,862,016 bytes [500 GB]
Sector Size: 512 bytes logical/physical
Device is: In smartctl database [for details use: -P show]
ATA Version is: 8
ATA Standard is: Exact ATA specification draft version not indicated
Local Time is: Wed Dec 12 03:34:39 2012 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: (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: ( 8160) seconds.
Offline data collection
capabilities: (0x7b) SMART execute Offline immediate.
Auto Offline data collection on/off support.
Suspend Offline collection upon new
command.
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: ( 2) minutes.
Extended self-test routine
recommended polling time: ( 83) minutes.
Conveyance self-test routine
recommended polling time: ( 5) minutes.
SCT capabilities: (0x3037) SCT Status 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 0x002f 200 200 051 Pre-fail Always - 486
3 Spin_Up_Time 0x0027 189 141 021 Pre-fail Always - 1525
4 Start_Stop_Count 0x0032 100 100 000 Old_age Always - 587
5 Reallocated_Sector_Ct 0x0033 200 200 140 Pre-fail Always - 0
7 Seek_Error_Rate 0x002e 200 200 000 Old_age Always - 0
9 Power_On_Hours 0x0032 098 098 000 Old_age Always - 1553
10 Spin_Retry_Count 0x0032 100 100 000 Old_age Always - 0
11 Calibration_Retry_Count 0x0032 100 100 000 Old_age Always - 0
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 578
192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 173
193 Load_Cycle_Count 0x0032 200 200 000 Old_age Always - 413
194 Temperature_Celsius 0x0022 097 093 000 Old_age Always - 46
196 Reallocated_Event_Count 0x0032 200 200 000 Old_age Always - 0
197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 0
198 Offline_Uncorrectable 0x0030 200 200 000 Old_age Offline - 5
199 UDMA_CRC_Error_Count 0x0032 200 200 000 Old_age Always - 0
200 Multi_Zone_Error_Rate 0x0008 200 200 000 Old_age Offline - 5
SMART Error Log Version: 1
ATA Error Count: 2
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 2 occurred at disk power-on lifetime: 1548 hours (64 days + 12 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
-- -- -- -- -- -- --
04 51 01 30 4f c2 a0 Error: ABRT
Commands leading to the command that caused the error were:
CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name
-- -- -- -- -- -- -- -- ---------------- --------------------
b0 d6 01 be 4f c2 a0 02 00:02:58.316 SMART WRITE LOG
b0 da 01 00 4f c2 a0 02 00:02:58.259 SMART RETURN STATUS
80 44 00 00 44 57 a0 02 00:02:58.259 [VENDOR SPECIFIC]
b0 d6 01 be 4f c2 a0 02 00:02:58.241 SMART WRITE LOG
80 45 00 01 44 57 a0 02 00:02:58.241 [VENDOR SPECIFIC]
Error 1 occurred at disk power-on lifetime: 1515 hours (63 days + 3 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
-- -- -- -- -- -- --
04 51 01 30 4f c2 a0 Error: ABRT
Commands leading to the command that caused the error were:
CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name
-- -- -- -- -- -- -- -- ---------------- --------------------
b0 d6 01 be 4f c2 a0 02 00:02:21.841 SMART WRITE LOG
b0 da 01 00 4f c2 a0 02 00:02:21.784 SMART RETURN STATUS
80 44 00 00 44 57 a0 02 00:02:21.784 [VENDOR SPECIFIC]
b0 d6 01 be 4f c2 a0 02 00:02:21.768 SMART WRITE LOG
80 45 00 01 44 57 a0 02 00:02:21.768 [VENDOR SPECIFIC]
SMART Self-test log structure revision number 1
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error
# 1 Conveyance offline Completed without error 00% 1552 -
# 2 Conveyance offline Completed: read failure 90% 1548 787927349
# 3 Conveyance offline Completed: read failure 90% 1515 883391611
# 4 Short offline Completed without error 00% 1503 -
# 5 Short offline Completed without error 00% 1503 -
# 6 Short offline Aborted by host 80% 1502 -
# 7 Extended offline Completed without error 00% 9 -
# 8 Short offline Completed without error 00% 6 -
# 9 Short offline Aborted by host 90% 6 -
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.
As you can see, on one hand one conveyance offline was completed with read failure. But, on the other hand, all attributes seems good – for instance, Reallocated_Sector_Ct is 0.
I also tried once again to cat the whole disk to /dev/null – and again I have errors in dmesg:
root@Microknoppix:/home/knoppix# nice -n 20 ionice -c 3 cat /dev/sda > /dev/null
During this cat dmesg shows such errors:
knoppix@Microknoppix:~$ dmesg
(...)
[ 504.003363] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
[ 504.003374] ata1.00: failed command: READ DMA EXT
[ 504.003383] ata1.00: cmd 25/00:00:80:07:01/00:02:00:00:00/e0 tag 0 dma 262144 in
[ 504.003385] res 40/00:00:09:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout)
[ 504.003389] ata1.00: status: { DRDY }
[ 509.016652] ata1: link is slow to respond, please be patient (ready=0)
[ 514.030002] ata1: soft resetting link
[ 514.200386] ata1.00: configured for UDMA/133
[ 514.200420] ata1: EH complete
[ 546.003333] ata1: lost interrupt (Status 0x50)
[ 546.003364] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
[ 546.003371] ata1.00: failed command: READ DMA EXT
[ 546.003380] ata1.00: cmd 25/00:00:80:15:06/00:02:00:00:00/e0 tag 0 dma 262144 in
[ 546.003381] res 40/00:00:09:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout)
[ 546.003386] ata1.00: status: { DRDY }
[ 546.003401] ata1: soft resetting link
[ 546.181205] ata1.00: configured for UDMA/133
[ 546.181234] ata1: EH complete
I thought it can be fault of motherboard or data cable that connects disk to motherboard. So I connected another disk to my motherboard using the same cable and slot and cated it to /dev/null. It succedeed without dmesg showing any errors.
Best Answer
There are no reallocated sectors because they failed to reallocate. Your drive is showing 5 Offline_Uncorrectable sectors, which happens when automatic repair fails. There are obvious read failures shown in the dmesg output, SMART errors, and read failures from SMART tests. There are ways of repairing these sectors as you have mentioned in the question, but from my experience it is a very short-term fix.
Replace the drive.