On 9/5/20 12:50 PM, Gregory Nowak wrote:
> On Sat, Sep 05, 2020 at 12:26:21PM +0900, Simon Walter wrote:
>> Reallocation, to my knowledge, should happen in the background. It's
>> *possible* that the reallocation event and the FS corruption are unrelated.
>
> My understanding is that the drive won't attempt to reallocate a
> sector until that sector is written to. So, if the e2fsck -f did try
> to write to that sector, the drive did reallocate it in the
> background. I do stand to be corrected as always.
>

Interesting. I think reallocation also happens as part of SMART self
checks and reads.

I am not sure where I read this. A disk will try to read a sector and if
it detects that the magnetism is weaker than it ought to be or any other
oddities, it reallocates the data. Though in golinux situation, maybe
the disk was not turned on for a long time. So the disk controller never
could detect the failing sector(s).

https://serverfault.com/questions/531553/how-to-find-files-affected-by-reallocated-sectors

I've read similar explantions since... since we "lost" the ability to
low level format disks.

I am really interested in what does "short read" mean. I guess it means
that not all data could be read, but is it a SATA error or an FS error?

I have had this error from a disk while it was plugged in via USB.
Plugging it in via SATA caused the disk to complete the fsck without
short reads and then I put it back into the USB case, and it continued
to function. I have had USB controllers behave like this so many times,
that I don't try and inspect disks in USB cases anymore.

Best regards,

Simon