Bad Blocks... Should I RMA?

Bruce Cran bruce at
Mon Nov 16 21:44:26 UTC 2009

On Mon, 16 Nov 2009 19:23:58 +0100
Roland Smith <rsmith at> wrote:

> Install the smartmontools port, and check the drive with 
> 'smartctl -a /dev/ad4'. If you see a non-zero Reallocated_Sector_Ct,
> RMA it immediately, as it is about to fail. If see other errors
> reported, RMA it.
> (S)ATA disk have spare sectors available. If a sector fails, it is
> replaced by one of the spares by the firmware. If you see a non-zero
> Reallocated_Sector_Ct, it means that the drive has run out of spares.
> This is bad news.

Surely it's the other way around - if you see a value of zero in the
"value" column the drive has run out of spare sectors and it's time to
RMA the drive? From what I've seen the 'raw' column appears to count
the number of sectors the drive has remapped using the spares buffer.
If it gets into the hundreds it's probably time to think about RMA'ing
the drive - if you trust that the 'raw' column is reporting what you
think it is (you should really only base your decision on the value,
worst and threshold columns).

Bruce Cran

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