Date: Tue, 30 Oct 2007 04:09:50 +0000 From: Thomas Hurst <tom.hurst@clara.net> To: Kevin Thompson <antiduh@csh.rit.edu> Cc: Felipe Neuwald <felipe@neuwald.biz>, freebsd-geom@freebsd.org Subject: Re: Raid 0 + 1 Message-ID: <20071030040950.GA76585@voi.aagh.net> In-Reply-To: <4414.147.177.192.113.1193678595.squirrel@angst.csh.rit.edu> References: <4414.147.177.192.113.1193678595.squirrel@angst.csh.rit.edu>
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* Kevin Thompson (antiduh@csh.rit.edu) wrote:
> Now we're going to pull together the d partion on each drive, create
> pairwise stripes, then mirror the new stripes together.
> gstripe label -vh -s 131072 st0 /dev/label/geom0s1d /dev/geom1s1d
> gstripe label -vh -s 131072 st1 /dev/label/geom2s1d /dev/geom3s1d
>
> We should now have two new devices '''/dev/stripe/st0''' and
> '''/dev/stripe/st1'''. Now mirror those two devices to create our final
> device that will next be used for the rest of our filesystems:
> gmirror label -vh gm0 /dev/stripe/st0 /dev/stripe/st1
Er, shouldn't you be doing this the other way around? Make two mirrors,
then stripe across them. IO performance should be identical in the
normal case, degrade less with a single disk failure (since only one
disk drops out of the array instead of an entire pair), and it'll be
more likely to survive a two disk failure.
--
Thomas 'Freaky' Hurst
http://hur.st/
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