RE: hot spare disk

["Walden H. Leverich" <WaldenL@xxxxxxxxxxxxxxx>]

> A "hot spare" drive is simply an empty drive already installed 
> in the machine and ready to be used automatically.

OK, I think we're splitting hairs here, and we're actually agreeing. In
RAID6, it's not a "spare" it is indeed part of the array, yes. But it's
a spare as in you can lose one and still be 100% protected.

In RAID5 you can have a true "spare" in the machine, as it it's not in
use by anything but it's there. However, I would not consider it "hot"
since it's not available at the time of the event (T0). Even if moved
into the array at T0, there is array rebuild time, call it N, such that
you're _unprotected_ from T0 to T0+N, hence not "hot". Warm? Yes. Hot,
no. :)

-Walden