Bad SSD drive - what happens with unreadable data

[peter.blok at bsd4all.org]

Hi Ken,

Yes I already had changed the time-outs and retries. I ended up using ddrescue out of the ports collection. Despite the amount of read errors I was able to recover the important stuff.

SSD drive is going back under warranty (hopefully). It is less than a year old and hardly used.

Peter

> On 13 Jun 2019, at 15:34, Kenneth D. Merry <ken at kdm.org> wrote:
> 
> On Thu, Jun 13, 2019 at 13:02:48 +0200, peter.blok at bsd4all.org wrote:
>> Hi,
>> 
>> I have a bad SSD drive. If I read it with dd and conv=noerror, what happens with the unreadable areas? Does it fill with zeroes, or does the driver still copy what it was able to read?
>> 
>> I???m getting ATA status 51 back, many blocks in a row. Followed by chunks of readable data, followed by unreadable data.
>> 
>> Is there a modepage or something else to tell the drive to pass on the bad data?
>> 
>> Any other ideas?
> 
> You might try the recoverdisk(1) utility.  It is designed for that sort of
> situation.
> 
> One of the recommendations in the recoverdisk(1) man page is to lower the
> retry count for the disk driver you're using, so you don't wind up retrying
> a lot in situations where the drive itself has tried and failed to read the
> data.
> 
> In looking at the source, it appears tht it will only write out the blocks
> it is able to read successfully.  IMO, it would be good to have at least an
> option to write zeros in output file in the areas where the reads failed.
> 
> Ken
> -- 
> Kenneth Merry
> ken at kdm.org