Re: writing zeros to bad sector results in persistent read error

[Phillip Susi <psusi@ubuntu.com>]

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On 6/9/2014 8:09 PM, Chris Murphy wrote:
> But what I'm reporting is an instance where an ATA Secure Erase 
> definitely did not fix up a single one of the bad sectors. Maybe 
> that's consistent with the spec, I don't know, but it's not what
> I'd expect seeing as every sector, those with an without LBA's
> assigned, are overwritten. Yet pending sectors were not remapped.
> Further, with all sectors overwritten by software (not merely the
> ATA Secure Erase command) yields no errors yet SMART reports there
> are still pending sectors, yet it's own extended test says there
> are none. I think that's bad behavior. But perhaps I don't
> understand the design and it's actually working as designed.

It sounds like what happened is the secure erase successfully rewrote
the sectors that were already flagged as pending, but did not
decrement the pending count.

FYI, rather than continuing to run a smart selftest to find one
sector, then use dd to fix it, and repeat, it would be much faster to
use the badblocks utility to read and rewrite the whole drive.  You
will want to make sure to use the correct sector size, and a
sufficiently large batch size for good performance.

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