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@comcast.net wrote:
On 08/10/2017 11:06 AM, Chris Murphy wrote:
On Thu, Aug 10, 2017, 6:48 AM Robert Moskowitz rgm@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.
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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
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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