Hard Drive Failure in FreeNas 11.1

[RickRepsher55]

Over the weekend, I got a hard drive failure message from our FreeNAS unit.

> GEOM_MULTIPATH: Error 5, da24 in disk9 marked FAIL
> GEOM_MULTIPATH: da8 is now active path in disk9

I checked the multipath's and:
multipath/disk9 degraded
da8 fail
da24 active

But on the unit I do not see any error lights to indicate the drive at fault.

What am I missing?

Thanks!
Rick