Re: A tool for remapping bad sectors in CURRENT?

Eugeny N Dzhurinsky wrote:
> Hello, all!
>
> Recently I've started to see the following logs in messages:
>
> Mar  8 12:00:24 localhost smartd[795]: Device: /dev/ad4, 2 Currently unreadable (pending) sectors
> Mar  8 12:00:24 localhost smartd[795]: Device: /dev/ad4, 2 Offline uncorrectable sectors
>
> smartctl did really show that something is wrong with my HDD, but still no
> remaps - just read errors.
>
> SMART Self-test log structure revision number 1
> Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
> # 1  Extended offline    Completed: read failure       60%      1198         222342559
> # 2  Extended offline    Completed: read failure       60%      1187         222342557
> # 3  Extended offline    Completed: read failure       60%      1180         222342559
> # 4  Short offline       Completed without error       00%      1178         -
> # 5  Extended offline    Aborted by host               90%      1178         -
>
> and
>
> ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
> ...
> Reallocated_Sector_Ct   0x0033   100   100   036    Pre-fail  Always       -       0
> ...
>
> Now can I find out which file owns the LBAs 222342557 and 222342559 ? How do I
> force remapping of these sectors? I assume that I have to write something
> directly to the sectors?

We have this problem from time to time on bunch of machines. As we are 
using gmirror, the easiest way is to force re-synchronization (rewrite) 
of the whole drive. The problem is when there are Pending unreadable 
sectors on both drives - it ends up with read error and some file(s) are 
corrupted, but there is no easy way (on FreeBSD) to find what file.

I tried it in the past with fsdb / findblk, but it does not work as I 
expect or I do not fully understand the needed calculations with slices 
+ partitions offsets / LBAs and right meaning of the term "block". It 
seems there are several meaning in different contexts.

It would be nice if somebody with enough FS / GEOM knowledge can write 
some HowTo or shell script to do the calculations and operations to find 
file containing bad sector(s) and put it in FAQ, Handbook, or Wiki.

Miroslav Lachman