[smartmontools-support] disk not reallocating bad sectors

Jürgen Bausa Juergen.Bausa at web.de
Thu Oct 28 13:22:54 CEST 2021

Dear Bruce and Franc,

> Von: "Bruce Allen" <bruce.allen at aei.mpg.de>
> Alternatively, use the "write long" command to write 
> inconsistent checksum data to those sectors (ie, keep on corrupting 
> those sectors) until eventually the disk steps trying to reuse them.

> Von: "Franc Zabkar" <fzabkar at internode.on.net>
> Could you use the WRITE UNCORRECTABLE command to flag that sector as 
> bad, and then follow it up with fsck / chkdsk / scandisk so that it is 
> recorded by the OS as being unavailable for use?

thanks for the support. If I undersatnd correctly both of you propose something 
comparable: to explicitly mark the pending sectors as "bad" and wait for
the drive to reallocate them.

I searched the internet for "write long" and "WRITE UNCORRECTABLE". Seems most
of the methods dont work on modern drives. But I found the --make-bad-sector
flag of hdparm, which should do something comparable. Is this what you meant?

So I marked the sectors as bad, overwrote them and did the same thing again.
After this no pending sectors (but reallocation count still at zero) and the 
next day I again had the pending sector. So it didnt work.

Or should I mark the sectors as bad and then just wait what is happening?
Would it be worth a try?

I already wrote to WD but didnt get an answer yet.

And I found out about the -c flag of fsck.ext4. It will check the whole disk for
beeing readable and then the bad sectors on a filesystem level for not beeing usable.
This way I will still have the pending sectors in the smartctl output but I can be sure
that the filesystem will not use them. No risk of loosing data.



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