Re: [9fans] SMART: Silly Marketing Acronym, Rebuts Truth

[Bakul Shah <bakul@bitblocks.com>]

On Feb 3, 2018, at 3:59 PM, Lyndon Nerenberg <lyndon@orthanc.ca> wrote:

>> The interesting thing (for me) was that
>> the SMART data from the drive gave it an all clear right to the end. But
>> unlike the SSDs, there was plenty of behavioural warning to remind me to
>> have the backups up to date and a spare at the ready...
> 
> FWIW, of the three-four dozen or so drives I have actively SMART monitored over the years, of the ones that failed, *not* *one* gave a SMART warning before dying.
> 
> That includes a spinny disk in one of my Mac Minis.  Of anyone, I would expect Apple to be in bed with their HD suppliers enough to have HD firmware that reliably reports SMART errors (since the disk utilities do pay attemtion to it).  I spent a month listening to that drive's heads slam back to the home position as it tried to recalibrate itself, before eventually dying. To the bitter end, SMART reported "a-ok boss!"

I have only monitored disks @ home and for them SMART does report
all sorts of things. For recalibration to have kicked in, you should seeing
lots of errors. It’s possible Apple s/w dumbs it down & presents just one
binary choice to the user but the underlying data should be there. It’s
usually host s/w that falls short. Given disks’ bathtub error curve, s/w
should show error rate as a graph (as a function of time) from the
beginning and recommend replacement as the rate starts climbing
again. Ideally it should even compare it with averaged error data
collected by the vendor. History and good visualization can be very
helpful.