ada0, 1 Currently unreadable (pending) sectors

[prieth]

Hello guys!

I've ran into kind of a problem wich I'm struggling to solve.

A few days ago my FreeNAS 11 gave me this critical alert:
Device: /dev/ada0, 1 Currently unreadable (pending) sectors
Device: /dev/ada0, 1 Offline uncorrectable sectors

So I logged onto the console and did a smartctl

Code:

 smartctl -t long /dev/ada0 

A few hours later the test was done and I was looking for the LBA_of_first_error to zero out the bad sector(s) with dd.

Code:

dd if=/dev/zero of=/dev/ada0 bs=??? count=1 seek=???

But the smartctl output says that there are no errors and everything is fine?
Any Ideas what's going on here?
Cheers legends!

Here's the smartctl -a /dev/ada0 output

Code:

=== START OF INFORMATION SECTION ===
Model Family:	 Western Digital Green
Device Model:	 WDC WD20EARX-00PASB0
Serial Number:	WD-WMAZA8456369
LU WWN Device Id: 5 0014ee 25c345eff
Firmware Version: 51.0AB51
User Capacity:	2,000,398,934,016 bytes [2.00 TB]
Sector Sizes:	 512 bytes logical, 4096 bytes physical
Device is:		In smartctl database [for details use: -P show]
ATA Version is:   ATA8-ACS (minor revision not indicated)
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is:	Sat Sep 30 11:28:21 2017 CEST
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:	  (  41) The self-test routine was interrupted
										by the host with a hard or soft reset.
Total time to complete Offline
data collection:				(37200) 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:		( 359) minutes.
Conveyance self-test routine
recommended polling time:		(   5) minutes.
SCT capabilities:			  (0x3035) 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	   -	   132
  3 Spin_Up_Time			0x0027   163   160   021	Pre-fail  Always	   -	   6825
  4 Start_Stop_Count		0x0032   100   100   000	Old_age   Always	   -	   617
  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   096   096   000	Old_age   Always	   -	   2995
 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	   -	   614
192 Power-Off_Retract_Count 0x0032   200   200   000	Old_age   Always	   -	   103
193 Load_Cycle_Count		0x0032   162   162   000	Old_age   Always	   -	   116989
194 Temperature_Celsius	 0x0022   106   094   000	Old_age   Always	   -	   44
196 Reallocated_Event_Count 0x0032   200   200   000	Old_age   Always	   -	   0
197 Current_Pending_Sector  0x0032   200   200   000	Old_age   Always	   -	   1
198 Offline_Uncorrectable   0x0030   200   200   000	Old_age   Offline	  -	   1
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	  -	   154

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 captive	Interrupted (host reset)	  90%	  2978		 -
# 2  Short captive	   Interrupted (host reset)	  90%	  2978		 -
# 3  Extended offline	Interrupted (host reset)	  70%	  2960		 -
# 4  Short offline	   Completed without error	   00%	  2957		 -

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.

 

[danb35]

# 1 Extended captive Interrupted (host reset) 90% 2978 -

Your SMART test never finished because you rebooted the machine when it was only about 10% done. In fact, this disk has never had a completed long SMART test.

 

[Ericloewe]

A few hours later the test was done and I was looking for the LBA_of_first_error to zero out the bad sector(s) with dd.

Why? That doesn't accomplish anything. It doesn't solve anything (ZFS would've fixed anything that needed fixing), it doesn't prolong the life of your hard drive and it might not even work at all.

It's a waste of time.

What is really confusing me is the "extended captive" test. I've never heard of such a thing. What's the year of manufacture for that drive?

In any case, the SMART data says that the drive is on its war out.

 

[prieth]

Sorry about that I got a bit confused.. now I did a smartctl -t long /dev/ada0

This is the output
SMART Self-test log structure revision number 1

Code:

Num  Test_Description	Status				  Remaining  LifeTime(hours)  LBA_of_first_error
# 1  Extended offline	Completed without error	   00%	  3003		 -
# 2  Extended captive	Interrupted (host reset)	  90%	  2978		 -
# 3  Short captive	   Interrupted (host reset)	  90%	  2978		 -
# 4  Extended offline	Interrupted (host reset)	  70%	  2960		 -
# 5  Short offline	   Completed without error	   00%	  2957		 -

no errors this time? But FreeNAS alert system still tells "Device: /dev/ada0, 1 Currently unreadable (pending) sectors"

the "extended captive" is when you run smartctl in captive mode like "smartctl -C.."
And with the dd thing... I thought once found the defect sectors I could force the HDD to replace them by writing with /dev/zero to the specific sector.

 

[Ericloewe]

the "extended captive" is when you run smartctl in captive mode like "smartctl -C.."

Reading the FreeBSD man page for smartctl:

WARNING: Tests run in captive mode may busy out the drive for the length of the test. Only run captive tests on drives without any mounted partitions!

Holy crap, that is a horrible idea. There is no reason to force the drive to operate like that.

And with the dd thing... I thought once found the defect sectors I could force the HDD to replace them by writing with /dev/zero to the specific sector.

If they're bad, the drive has probably already remapped them.

no errors this time? But FreeNAS alert system still tells "Device: /dev/ada0, 1 Currently unreadable (pending) sectors"

That has nothing to do with the test log. That warning is specifically covering the SMART attributes.

 

[BERKUT]

In my situation, if you have 1 pending section, you'll have after more and more and more, when OS try to read other sections near the bad sector.
It happened with my three hdd in row.

 

[Inxsible]

1 pending sector is no reason to throw the drive away. But make sure you keep an eye on it. Now would be a good time to buy the replacement drive and keep it ready (burn in etc). Once you start seeing the Pending sector count go up, replace the drive.

Another thing you could do is replace the drive immediately and use this drive in a non-critical environment -- maybe a secondary desktop or something.