Re: raid10 redundancy

[David T-G <davidtg-robot@justpickone.org>]

Phil, et al --

...and then Phil Turmel said...
% 
% I do this for my medium-speed read-mostly tasks.  Raid10,n3 across 4
% or 5 disks gives me redundancy comparable to raid6 (lose any two)
% without the CPU load of parity and syndrome calculations.

I've been reading and I still need to catch up on the notation, but how
much space do you get in the end?

I'm hoping to grow our disk farm and end up with 8+ disks.  I'm more than
a bit nervous about RAID5 across a bunch of 6T (or bigger) disks, so I've
been thinking of RAID6.  That would give me 6x6 = 36T plus two parity.

Putting 8 disks in RAID10 should give me 6x4 = 24T with mirroring.
That's a pretty hefty space penalty :-(  But ...

How does RAID10 across 5 disks as above 1) work and 2) work out?  If you
had 8 disks with a huge need for space, how would y'all lay out everything?


% 
% Phil


Thanks in advance :-)

:-D
-- 
David T-G
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See http://justpickone.org/davidtg/tofu.txt