Re: SATA hdd refuses to reallocate a sector?

From: Mark Lord
Date: Sun Jun 23 2013 - 17:41:49 EST

On 13-06-23 03:00 PM, Pavel Machek wrote:
> Thanks for the hint. (Insert rant about hdparm documentation
> explaining that it is bad idea, but not telling me _why_ is it bad
> idea. Can I expect cache consistency issues after that, or is it just
> simple "you are writing to the disk without any checks"? Plus, I guess
> documentation should mention what sector number is. I guess sectors
> are 512bytes for the old drives, but is it 512 or 4096 for new
> drives?)

For ATA, use the "logical sector size".
For all existing drives out there, that's a 512 byte unit.

> ...but it does not do the trick :-(. It behaves strangely as if it was
> still cached somewhere. Do I need to turn off the write back cache?

No, it works just fine. You probably have more than one bad sector.
After you see a read failure, run "smartctl -a" and look at the error
logs to see what sector the drive is choking on.

Or just low-level format it all with "hdparm --security-erase".

Mark Lord
Real-Time Remedies Inc.
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