[ale] possible to use hard drives that have bad blocks ?

[Scott Warfield]

You can use smartctl.

Here's an example of how to use it.
http://smartmontools.sourceforge.net/BadBlockHowTo.txt

 

-----Original Message-----
From: ale-bounces at ale.org [mailto:ale-bounces at ale.org] On Behalf Of Greg
Freemyer
Sent: Saturday, June 25, 2005 2:09 PM
To: Atlanta Linux Enthusiasts
Subject: Re: [ale] possible to use hard drives that have bad blocks ?

On 6/25/05, Courtney Thomas <ccthomas at joimail.com> wrote:
> I've got a couple of HDs that when I:
> 
> dd if=/dev/hdX of=/dev/null bs=1m
> 
> I get a single instance of something like:
> 
> FAILURE - READ_DMA status=51 <READY, DSC, ERROR> error=40 
> <UNCORRECTABLE> LBA=19194112 Input/output error
> 
> My question is: does this signify a single bad block and is there a 
> way to identify this error to some program that can block it's use, so 
> the drive can be used ?
> 
> Thank you,
> Courtney
> 

LBA is the Logical Block Address of the physical sector on the drive.

If indeed your only seeing one LBA address that is consistently bad you
should be able fix it.

If your a C programmer, you could open /dev/hdX, lseek to LBA * 512 and try
to read a sector (512) bytes.  It should cause the same error.
 If not, try (LBA - 1) * 512.

If you can find the sector, then modify your code to write to the sector.
That should either refresh the sector with a stronger magnetic field, or
cause an internal disk problem that causes the disk to reassign the sector
internally.

I would try the above before I started looking at filesystem level
solutions.

Unfortunately, I don't know of a standard Linux tool to do the above, but
I'm sure there is one.  (dd with the skip option is very slow because it
actually reads everything being skipped).

Greg
--
Greg Freemyer
The Norcross Group
Forensics for the 21st Century
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