[CentOS] Errors on an SSD drive

Fri Aug 11 13:53:18 UTC 2017
Robert Nichols <rnicholsNOSPAM at comcast.net>

On 08/10/2017 11:06 AM, Chris Murphy wrote:
> On Thu, Aug 10, 2017, 6:48 AM Robert Moskowitz <rgm at htt-consult.com> wrote:
> 
>>
>>
>> On 08/09/2017 10:46 AM, Chris Murphy wrote:
>>> If it's a bad sector problem, you'd write to sector 17066160 and see if
>> the
>>> drive complies or spits back a write error. It looks like a bad sector in
>>> that the same LBA is reported each time but I've only ever seen this with
>>> both a read error and a UNC error. So I'm not sure it's a bad sector.
>>>
>>> What is DID_BAD_TARGET?
>>
>> I have no experience on how to force a write to a specific sector and
>> not cause other problems.  I suspect that this sector is in the /
>> partition:
>>
>> Disk /dev/sda: 240.1 GB, 240057409536 bytes, 468862128 sectors
>> Units = sectors of 1 * 512 = 512 bytes
>> Sector size (logical/physical): 512 bytes / 512 bytes
>> I/O size (minimum/optimal): 512 bytes / 512 bytes
>> Disk label type: dos
>> Disk identifier: 0x0000c89d
>>
>>      Device Boot      Start         End      Blocks   Id  System
>> /dev/sda1            2048     2099199     1048576   83  Linux
>> /dev/sda2         2099200     4196351     1048576   82  Linux swap /
>> Solaris
>> /dev/sda3         4196352   468862127   232332888   83  Linux
>>
> 
> LBA 17066160 would be on sda3.
> 
> dd if=/dev/sda skip=17066160 count=1 2>/dev/null | hexdump -C
> 
> That'll read that sector and display hex and ascii. If you recognize the
> contents, it's probably user data. Otherwise, it's file system metadata or
> a system binary.
> 
> If you get nothing but an I/O error, then it's lost so it doesn't matter
> what it is, you can definitely overwrite it.
> 
> dd if=/dev/zero of=/dev/sda seek=17066160 count=1

You really don't want to do that without first finding out what file is using
that block. You will convert a detected I/O error into silent corruption of
that file, and that is a much worse situation.

-- 
Bob Nichols     "NOSPAM" is really part of my email address.
                 Do NOT delete it.