Alan McKinnon wrote:
> On Monday 24 March 2008, Enrico Weigelt wrote:
>  
>> does anyone know an (virtual) block device which can do automatic
>> defect management (if the underlying disks have badblocks) ?
>>
>> My idea goes like this:
>> * one or more devices are assigned to one block device
>> * a bunch of spare blocks are reserved for defect management
>>  (so the device looks smaller than the sum of assigned disks)
>> * if an badblock is detected, it's automatically remapped
>>  to an spare block
>>
>> In fact, just what drive-internal defect manangement does, but
>> at OS / driver level.
>>  
>
> I don't see the point, unless you are dealing with drives that do not
> have defect management.
>
> What makes you think you can accomplish this result better than the
> firmware on the drive? It seems to me that if the drive firmware missed
> the opportunity to relocate the bad block, then your window of
> opportunity to do it in your code has long since passed. IOW, the OS
> code cannot possibly ever achieve it's design result.
>
> Just a thought, maybe you know some aspect of disks that I don't and can
> see where this would be useful. From where I sit, I can;t see any such
> use-case.
>
>  

While I see what Alan is saying, I'm pretty sure LVM does it. Device
Drivers -> Multiple Devices Driver Support -> Bad Block Relocation
Device Target. I've never played with it but I assume there's a lot of
good reading on it.

--
HTH, Eric
--
gentoo-user@(protected)