Robert Nichols wrote: > On 08/11/2017 12:16 PM, Chris Murphy wrote: >> On Fri, Aug 11, 2017 at 7:53 AM, Robert Nichols >> <rnicholsNOSPAM at comcast.net> wrote: >>> 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. <snip> >>>> 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 ofthat file, and that is a much worse situation. >> >> Yeah he'd want to do an fsck -f and see if repairs are made, and also <snip> > fsck checks filesystem metadata, not the content of files. It is not going > to detect that a file has had 512 bytes replaced by zeros. If the file > is a non-configuration file installed from an RPM, then "rpm -Va" should > flag it. > > LVM certainly makes the procedure harder. Figuring out what filesystem > block corresponds to that LBA is still possible, but you have to examine > the LV layout in /etc/lvm/backup/ and learn more than you probably wanted > to know about LVM. I posted a link yesterday - let me know if you want me to repost it - to someone's web page who REALLY knows about filesystems and sectors, and how to identify the file that a bad sector is part of. And it works. I haven't needed it in a few years, but I have followed his directions, and identified the file on the bad sector. mark