[smartmontools-support] Extended test doesn't catch CurrentPendingSector and OfflineUncorrectableSector errors

[Christian Franke]

Dipanjan Das wrote:
>
> Hi Christian,
>
> Thanks for your detailed response.
>
> On Mon, 12 Jul 2021 at 04:14, Christian Franke 
> <Christian.Franke at t-online.de <mailto:Christian.Franke at t-online.de>> 
> wrote:
>
>
>     This log matches the ddrescue result. Read of (at least) LBA
>     3884004178
>     failed occasionally and worked again in later tests. Unfortunately
>     the
>     disk firmware did not redirect this weak sector.
>
>
> (197) Current_Pending_Sector is set to 1 for the last few weeks. Maybe 
> that sector refers to this one where the read fails intermittently?

Possibly, see below.


> I have run several extended checks since this error appeared, 
> hoping that it would get remapped, and (5) Reallocated_Sector_Ct will 
> bump up. Unfortunately, that didn't happen. Not sure if it's because 
> of the intermittent nature of the failure.

Overwriting the sector with same data should reallocate it.
Or: Check whether a file is affected (e.g. with sleuthkit). If any, copy 
the file to somewhere else and overwrite the original in-place (e.g. 
with shred).


>
> In the SMART attributes section, (198) Offline_Uncorrectable is set to 
> 6 for the last few weeks. Also, I am curious what's that related to.

Some drives do not clear this attribute on reallocation.
Some drives do not bump Reallocated_Sector_Ct on reallocation.
SMART attributes are not part of any ATA standard, so vendors could use 
any interpretation.


> ...
>
> Attached. Didn't pass '-q noserial' intentionally if that helps you in 
> any way.


>   9 Power_On_Hours          -O--CK   026 026   000    -    54399
> ...
>  12 Power_Cycle_Count       -O--CK   100   100   000    -    49

Operating 24/7 for 6+ years ?
I would suggest to replace this drive :-)


> After command completion occurred, registers were:
> ER -- ST COUNT  LBA_48  LH LM LL DV DC
> -- -- -- == -- == == == -- -- -- -- --
> 40 -- 51 00 80 00 e7 33 00 81 52 40 00  Error: UNC at LBA = 
> 0xe733008152 = 992993116498

This firmware uses the wrong byte order in this error log. Please retry with
   smartctl -l xerror -F xerrorlba ...

This may result in "LBA = 0xe7813352 = 3884004178" which then matches 
the LBA from the self-test log. This is possibly the Current_Pending_Sector.

Regards,
Christian