Re: [9fans] ata drive capabilities

[erik quanstrom <quanstro@quanstro.net>]

On Wed Dec 26 01:33:14 EST 2007, rminnich@gmail.com wrote:
> On Dec 25, 2007 6:59 PM, erik quanstrom <quanstro@quanstro.net> wrote:
> >(we have a drive
> > in the lab that smart declares will fail any minute now.  it's been
> > this way for 2 years.)
> 
> From everything I've seen, SMART has zero correlation with real
> hardware issues -- confirmed by a discussion with someone at a big
> search company. SMART is dumb.

the google paper shows a 40% afr for the first 6 months after some
smart errors appear.  (unfortunately they don't do numbers for
a simple smart status.)

from my understanding of how google do things, loosing a drive just
means they need to replace it.  so it's cheeper to let drives fail.
on the other hand, we have our main filesystem raided on an aoe
appliance.  suppose that one of those raids has two disks showing
a smart status of "will fail".  in this case i want to know the elevated
risk and i will allocate a spare drive to replace at least one of the
drives.

i guess this is the long way of saying, it all depends on how painful
loosing your data might be.  if it's painful enough, even a poor tool
like smart is better than nothing.

- erik