Re: Prepping to install: a digression

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Mon, 29 Jun 2015 22:54:19 -0453
    From:        "William A. Mahaffey III" <wam%hiwaay.net@localhost>
    Message-ID:  <55921174.3020101%hiwaay.net@localhost>

  | Which is right, the list & I or those lying man pages ?

The list, and the man pages, both say the same thing as I recall.

For any stripe on the raid, N-1 drives hold the data, and one drive
holds the parity.

Whether the same drive holds all the parity. or whether it is spread
around the drives was soething I said I wasn't sure about (in a previous
message on the list - relating to NetBSD's implementation).

But why do you care?   Unless you're planning on working on the raidframe
implementation, the only thing it affects is performance.   (Spreading the
parity around allows all drives to participate in normal read operations,
and the extra writes on write ops to be spread around all of the drives,
instead of leaving the parity drive idle on read ops, and a bottleneck on
writes).

Aside from that (and if you are seeking truly high performance, raid5 is not
the solution) it makes no difference at all to anything that you do, or
observe.

kre