to be clear I wasn't saying Smart is useless just that smartctl doesn't
always tell you every thing so you shouldn't rely as a definitive answer on
all issues on all disks.

As for raid controllers well that's a very long conversation there are good
reasons the enterprise ones do not, at least not directly in a way you can
extract using the smartctl command instead they have more advanced checks
available through the drivers and additional monitoring tools provided by
the manufacturer of the raid controller.

as for the predictive nature of smart well that's actually in its
specification it predicts errors based on indicators.

On Tue, Oct 16, 2018 at 7:55 PM Konstantin Olchanski <[log in to unmask]>
wrote:

> On Tue, Oct 16, 2018 at 04:20:03PM -0400, Paul Robert Marino wrote:
> >
> > smart is predictive and doesn't catch all errors its also not compatible
> > with all disks and controllers especially raid capable controllers.
> >
>
>
> Do not reject SMART as useless, it correctly reports many actual disk
> failures:
>
> a) overheating (actual disk temperature is reported in degrees Centigrade)
> b) unreadable sectors (data on these sectors is already lost) - disk model
> dependant
> c) "hard to read" sectors (WD specific - "raw read error rate")
> d) sata link communication errors ("CRC error count")
>
> even more useful actual (*not* predictive) stuff is reported for SSDs
> (again, model dependant)
>
> it is true that much of this information is disk model dependant and
> one has to have some experience with the SMART data to be able
> to read it in a meaningful way.
>
> as for raid controllers that prevent access to disk SMART data,
> they are as safe to use a car with a blank dashboard (no fuel level,
> no engine temperature, no speedometer, etc).
>
>
> --
> Konstantin Olchanski
> Data Acquisition Systems: The Bytes Must Flow!
> Email: olchansk-at-triumf-dot-ca
> Snail mail: 4004 Wesbrook Mall, TRIUMF, Vancouver, B.C., V6T 2A3, Canada
>