RE: hot spare disk

[PaulMmn <PaulMmn@xxxxxxxxxxxxx>]

Raid 6 is not a spare drive!  -both- of the 'extra' drives are 
actively participating in the set--  keeping either data or parity 
information at all times.  It's just an added extra when raid sets 
grow to 16, 24, or more drives!  It lets you have 2 drives in a 
single set fail and still not lose data.

I think I remember hearing about a 'real' hot spare-- up and spinning 
but with zero data and zero parity until one of the 'live' drives 
fails.

--Paul E Musselman
PaulMmn@xxxxxxxxxxxxxxxxxxxx



At 8:48 AM -0400 4/29/08, Walden H. Leverich wrote:
>  > RAID6 isn't Raid5 with Hot Spare. RAID6 uses 2 drives woeth of parity
> if
> > you will allowing you to loose '2' drives in the same set and still run
>
> > as you know.
>
> Yes, but therefore the "spare" drive is "hot". That is, it's up and
> running the second you lose the first one (ok, it was always running,
> but the point is there is zero-unprotected time.)
>
> In the case of RAID5 with a spare, it's "warm" at best. There is
> unprotected time as the array is rebuilt.
>
> -Walden