Re: feature suggestion to handle read errors during re-sync of raid5

[Richard Scobie <richard@sauce.co.nz>]

Mikael Abrahamsson wrote:

> Since the drive has ECC, it would be interesting to see the amount of
> read errors ECC has corrected. Would also be interesting to know if the
> drive will rewrite a sector if it's ECC corrected, so that ECC doesn't
> have to kick in next time (or if they're actually operating in so narrow
> margins that they actually use the ECC constantly because the s/n ratio
> is bad and that this is part of the design).

I guess this is manufacturer and model specific, but looking smartd 
output from a representative (as in similar errors etc to others of the 
same model) Seagate SCSI drive, they are not rewriting on ECC:

Error counter log:
            Errors Corrected by           Total   Correction 
Gigabytes    Total
                EEC          rereads/    errors   algorithm 
processed    uncorrected
            fast | delayed   rewrites  corrected  invocations   [10^9 
bytes]  errors
read:    2205106        0         0   2205106    2205106      18342.407 
           0
write:         0        0         0         0          0       3831.185 
           0


Regards,

Richard