"Senn, Bruce" <[log in to unmask]> wrote in message
news:8bydnZGJeY-w_1rdRVn-hQ@fidnet.com...
> So, a rough calculation gets me
>
> Hours in 3 months = 24*90 = 2160 =approx 2000
>
> If I "run" 500 drives for 3 months and have 1 failure I can claim a
> 1,000,000 MTBF
>
> 2000*500/1 = 1000000
>
> I suppose that's a reasonable test and result, particularly if I weed
> out the "infant mortality."
>

Wow.  You see one failure, and you're going to weed out the infant
mortalities?

The truth is, 500 drives run for 3 months will still be in their infant
mortality
stage, and you'll see lots more than just one failure.  So you're going to
estimate that just one of those failures would have happened if you had
been at the bottom of the bathtub curve?  Particularly since you don't
even know what the bathtub curve looks like?  This isn't science, it's
called "making up data", which basically is how MTBF figures are
created.

-Dave

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