Bad sector on drive ...

[Dan Nelson]

In the last episode (Feb 10), Marc G. Fournier said:
> Short of a reformat, any way of marking the following as bad? :(
> 
> Feb 10 02:27:20 ganymede kernel: ad4: FAILURE - READ_DMA  status=51<READY,DSC,ERROR> error=40<UNCORRECTABLE> LBA=176887263
> Feb 10 02:27:25 ganymede kernel: ad4: TIMEOUT - READ_DMA retrying (1 retry  left) LBA=176887324
> Feb 10 02:27:30 ganymede kernel: ad4: TIMEOUT - READ_DMA retrying (0 retries  left) LBA=176887324
> Feb 10 02:27:35 ganymede kernel: ad4: FAILURE - READ_DMA timed out LBA=176887324

Try writing to the block causing the error, using dd and the seek=
option; if the write succeeds, you're done (and the drive will have
either reused the block or reassigned it to a spare).  If it doesn't
succeed, copy what you can off the drive and toss it, since all its
spares are used up.

I think LBA numbers map directly to seek= values assuming you keep
bs=512 and access /dev/ad4 .  I'd try reading the bad block with dd to
verify it's the right one before doing a write, though.

-- 
	Dan Nelson
	dnelson at allantgroup.com