smartctl reports bad sectors, badblocks does not find any

[Juan R. de Silva]

I did the stupidest thing I could as to forget that I was running on 
battery while installing FreeBSD on a free (1st) partition. and I found 
the laptop shutting down when it was too late.

After this event smartctl consistently reports Read Failure starting on 
LBA 26203589, Current_Pending_Sector 1, and Offline_Uncorrectable 4. 
This block is within partition in question. Thus I know I damaged hdd 
within its boundries.  

Simply formating this partition certainly did not help.

I've run dd if=/dev/zero of=/dev/sda1 both starting with the reported LBA 
and then on the entire partition. And I still have same report from 
smartctl

I run badblocks on the partition firs in non-destructive and then in 
destructive (read/write) mode in both cases badblocks reported 0 errors. 
But smartctl still gives me the same report.

In all the cases I run smartctl -t offline /dev/sda1 just to ensure 
smartctl updates its data before I run final smartctl -A /dev/sda

Any suggestions folks? It drives me crazy. I'm fighting it 2 days for now.

[JB]

Juan R. de Silva <juan.r.d.silva <at> gmail.com> writes:

>  ... 
Do you see the same SMART errors under your other distros ?

Suggestions:
1. see if BIOS has harddisk self-test (read; read-write)
2. check your hd manufacturer's web site for diagnostics/repair utility
3. $ man hdparm
   # hdparm -I /dev/sd?
   study it (I have not tried it myself ...)
   VERY DANGEROUS  according to manual !
   --make-bad-sector
   --read-sector
   --repair-sector
   --write-sector
   
JB

[Juan R. de Silva]

On Sat, 25 Dec 2010 00:00:45 +0800, Ian Chapman wrote:

>  On 24/12/10 11:46, Juan R. de Silva wrote:
> >
> >> I haven't used badblocks, but suspect that the hard disk drive
> >> electronics is clever enough to hide damage and relocate bad sectors.
> >> The S.M.A.R.T. electronics will still know they are there, though.
> >
> > OK. This might be the answer to a question I had: why badblocks never
> > found them but smartctl did.
>  
>  AFAIK smartctl doesn't actually "detect" bad sectors on a disk, it just
>  reports what it sees in the SMART counters. 
Very much true. Bad wording from my part. What I wanted to say that the 
bad sector was reported by smartctl but was not detected by badsectors, 
when run on the drive.

>  The particular counter is 
>  Current_Pending_Sector I believe. Each time the disk encounters
>  a sector it can't read, the firmware increments this counter.
>  Only when that bad sector is written to, does the disk remap the sector 
>  and usually Current_Pending_Sector decreases by 1. 
In my case I never was able to achieve this. I wrote to the sector in 
question directly with dd, I did it running badblocks in destructive 
(read/write) mode - the values of Current_Pending_Sector and 
Offline_Uncorrectable remained still.

>  I have however seen on occasions,
>  the counter increase but no bad sector appears to be on the disk. I just
>  put this down to a temporary glitch, ie the disk at some short point in
>  time could not read that sector but now it's fine, however the increment
>  remains. Some drives I believe also increment Reallocated_Sector_Ct
>  every time a remap is done, but certainly many do it 'silently'. 
This value for my disk is quite high sinc the drive is 4.5 years old. 
It's not a lot for a 3.5" drive but is much enough for a laptop drive 
(Dell Latitude d820) I think. Though I'm still disappointed. I expected 
it to last more.
 
>  You can perform a disk test using smartctl (sounds like you have
>  already)  
You bet. :-)

>  The last value is the LBA which can used with hdparm --write-sector
> to
>  write to that specific sector triggering a remap and usually
>  decrementing the counter. Be extremely careful when using this command
>  though as a slight mistake can trash data. 
As I've mentioned in one of my posts, this the only thing I did not do 
yet. I'll probably do it on the bad sector reported in 
Current_Pending_Sector (the value is 1) since I know it's starting LBA 
and I know the block size. But I have no idea what to do with those 
reported in Offline_Uncorrectable - the value here is 4. 

And it looks like actually Offline_Uncorrectable gives me more of 
warning. I looked through my log files and found that it was reported the 
first with the lower value a couple of months ago. Than a month later it 
increased, while Current_Pending_Sector remained 1. My bad, I've 
neglected my log files for a while.

[Juan R. de Silva]

On Fri, 24 Dec 2010 18:48:31 -0700, James McKenzie wrote:

>  On 12/23/10 10:34 PM, JB wrote:
> > Juan R. de Silva<juan.r.d.silva<at>  gmail.com>  writes:
> >
> >> ...
> > Do you see the same SMART errors under your other distros ?
> >
> > Suggestions:
> > 1. see if BIOS has harddisk self-test (read; read-write) 2. check your
> > hd manufacturer's web site for diagnostics/repair utility 3. $ man
> > hdparm
> >     # hdparm -I /dev/sd?
> >     study it (I have not tried it myself ...) VERY DANGEROUS  according
> >     to manual ! --make-bad-sector
> >     --read-sector
> >     --repair-sector
> >     --write-sector
> >
>  I highly recommend NOT trying to fix bad sectors.  Just look and see if
>  the number is increasing as you use the drive.  If it does, time to get
>  another/RMA this drive. 
I guess I've done enough in this regard already :-). The only thing I'm 
still hesitating to try (but considering) is hdparm.

At the end if the drive is destined to die, I at least have a good 
opportunity to exercise on it. :-)

>  BTW, the OP did not state who the manufacturer of the drive is,
It's FUJITSU MHV2100BH on Dell Latitude d820. And it's 4.5 years old.

>  but some
>  manfacturers are known to have drives that ship with recovered bad
>  sectors that S.M.A.R.T. finds bad after very little use. 
Unfortunately my logs show the first report of Nov. 23 this year.

Well, I guess there is not much I can do but making full backups 
frequently.

[James McKenzie]

On 12/23/10 10:34 PM, JB wrote:
>  Juan R. de Silva<juan.r.d.silva<at>  gmail.com>  writes:
>
> > ...
>  Do you see the same SMART errors under your other distros ?
>
>  Suggestions:
>  1. see if BIOS has harddisk self-test (read; read-write)
>  2. check your hd manufacturer's web site for diagnostics/repair utility
>  3. $ man hdparm
>      # hdparm -I /dev/sd?
>      study it (I have not tried it myself ...)
>      VERY DANGEROUS  according to manual !
>      --make-bad-sector
>      --read-sector
>      --repair-sector
>      --write-sector
>  
I highly recommend NOT trying to fix bad sectors.  Just look and see if 
the number is increasing as you use the drive.  If it does, time to get 
another/RMA this drive.

BTW, the OP did not state who the manufacturer of the drive is, but some 
manfacturers are known to have drives that ship with recovered bad 
sectors that S.M.A.R.T. finds bad after very little use.

James McKenzie

[Ian Chapman]

On 24/12/10 11:46, Juan R. de Silva wrote:
> > I haven't used badblocks, but suspect that the hard disk drive
> > electronics is clever enough to hide damage and relocate bad sectors.
> > The S.M.A.R.T. electronics will still know they are there, though.
>
>  OK. This might be the answer to a question I had: why badblocks never
>  found them but smartctl did. 
AFAIK smartctl doesn't actually "detect" bad sectors on a disk, it just 
reports what it sees in the SMART counters. The particular counter is 
Current_Pending_Sector I believe. Each time the disk encounters a sector 
it can't read, the firmware increments this counter. Only when that bad 
sector is written to, does the disk remap the sector and usually 
Current_Pending_Sector decreases by 1. I have however seen on occasions, 
the counter increase but no bad sector appears to be on the disk. I just 
put this down to a temporary glitch, ie the disk at some short point in 
time could not read that sector but now it's fine, however the increment 
remains. Some drives I believe also increment Reallocated_Sector_Ct 
every time a remap is done, but certainly many do it 'silently'.

You can perform a disk test using smartctl (sounds like you have 
already) to find the LBA of a bad sector. The output of smartctl -a, 
once the test completes, provides test results which look a little like:

Num  Test_Description    Status                  Remaining 
LifeTime(hours)  LBA_of_first_error
# 1  Extended offline    Completed without error       00%     13397 
      -
# 2  Extended offline    Completed without error       00%     13293 
      -
# 3  Selective offline   Completed without error       00%     13290 
      -
# 4  Selective offline   Completed without error       00%     13290 
      -
# 5  Selective offline   Completed: read failure       70%     13290 
      379731309
# 6  Selective offline   Completed: read failure       70%     13290 
      379729059
# 7  Extended offline    Completed: read failure       50%     13290 
      379718855

The last value is the LBA which can used with hdparm --write-sector to 
write to that specific sector triggering a remap and usually 
decrementing the counter. Be extremely careful when using this command 
though as a slight mistake can trash data.


-- 
Ian Chapman.

[Juan R. de Silva]

On Fri, 24 Dec 2010 05:34:33 +0000, JB wrote:

>  Juan R. de Silva <juan.r.d.silva <at> gmail.com> writes:
>  
> > ...
>  
>  Do you see the same SMART errors under your other distros ? 
Yes, the same errors under all of them. I've tried it under 
systemrescuecd 
- same results.
 
>  Suggestions:
>  1. see if BIOS has harddisk self-test (read; read-write)  
No, it does not have it.

>  2. check your
>  hd manufacturer's web site for diagnostics/repair utility  
There is only DOS and only diagnostic utility. I've not tried it yet, 
since it does not have any repair option anyway.

>  3. $ man
>  hdparm
>     # hdparm -I /dev/sd?
>     study it (I have not tried it myself ...) VERY DANGEROUS  according
>     to manual ! --make-bad-sector
>     --read-sector
>     --repair-sector
>     --write-sector 
That is a very good suggestion. I've totally forgotten about hdparm. This 
is the only thing I've not tried yet. I'll try it the next few days, 
since I get busy with other things right now.

Thank you.

[Juan R. de Silva]

On Thu, 23 Dec 2010 20:04:22 -0500, Ted Roche wrote:

>  On 12/23/10, Juan R. de Silva <juan.r.d.silva(a)gmail.com&gt;
> wrote:
>  
> > I did the stupidest thing I could as to forget that I was running on
> > battery while installing FreeBSD on a free (1st) partition. and I found
> > the laptop shutting down when it was too late.
>  
>  This shouldn't have caused hard disk drive damage; modern hardware
>  should be smart enough to shut down safely on power failure. 
You may be right. It is very much possible that I had some bad sectors 
before and did not noticed them.  It does look like there were just few 
of them and they were managed by hardware. At least neither of my Lunux 
OSs never thrown any related errors.

I was not sure myself but I've noticed the problem after the described 
accident.  Hence the blame...

>  I haven't used badblocks, but suspect that the hard disk drive
>  electronics is clever enough to hide damage and relocate bad sectors.
>  The S.M.A.R.T. electronics will still know they are there, though. 
OK. This might be the answer to a question I had: why badblocks never 
found them but smartctl did.

>  I have had some success recovering disk errors following the
> guidance
>  here:
>  
>  http://smartmontools.sourceforge.net/badblockhowto.html 
I have actually followed the same howto without any success. After 
completion of all suggested steps I still had them reported by smartctl 
at the same place. But keeping in mind suggested by you above, this might 
be because the author of the howto dealt with bad sectors of logical 
nature rather then hardware nature.

Thanks for suggestions.

[Ted Roche]

On 12/23/10, Juan R. de Silva <juan.r.d.silva(a)gmail.com&gt; wrote:

>  I did the stupidest thing I could as to forget that I was running on
>  battery while installing FreeBSD on a free (1st) partition. and I found
>  the laptop shutting down when it was too late. 
This shouldn't have caused hard disk drive damage; modern hardware
should be smart enough to shut down safely on power failure.

I haven't used badblocks, but suspect that the hard disk drive
electronics is clever enough to hide damage and relocate bad sectors.
The S.M.A.R.T. electronics will still know they are there, though.

I have had some success recovering disk errors following the guidance here:

http://smartmontools.sourceforge.net/badblockhowto.html

-- 
Ted Roche
Ted Roche & Associates, LLC
http://www.tedroche.com

[Juan R. de Silva]

On Thu, 23 Dec 2010 22:36:46 +0000, Juan R. de Silva wrote:

>  I did the stupidest thing I could as to forget that I was running on
>  battery while installing FreeBSD on a free (1st) partition. and I found
>  the laptop shutting down when it was too late.
>  
>  After this event smartctl consistently reports Read Failure starting on
>  LBA 26203589, Current_Pending_Sector 1, and Offline_Uncorrectable 4.
>  This block is within partition in question. Thus I know I damaged hdd
>  within its boundries.
>  
>  Simply formating this partition certainly did not help.
>  
>  I've run dd if=/dev/zero of=/dev/sda1 both starting with the reported
>  LBA and then on the entire partition. And I still have same report from
>  smartctl
>  
>  I run badblocks on the partition firs in non-destructive and then in
>  destructive (read/write) mode in both cases badblocks reported 0 errors.
>  But smartctl still gives me the same report.
>  
>  In all the cases I run smartctl -t offline /dev/sda1 just to ensure
>  smartctl updates its data before I run final smartctl -A /dev/sda
>  
>  Any suggestions folks? It drives me crazy. I'm fighting it 2 days for
>  now. 
Anybody to help? 

And, yes, I've forgotten to mention - I have a multiboot multidistro 
system running Fedora 13, Ubuntu 10.04, and openSuse 11.3. FreeBSD was 
dumped after the incident. 

Though I think it is not really relevant to the case.