Date: Thu, 21 Sep 2006 02:30:37 -0700 (PDT) From: "R. B. Riddick" <arne_woerner@yahoo.com> To: Matthew Seaman <m.seaman@infracaninophile.co.uk>, "Marc G. Fournier" <freebsd@hub.org> Cc: freebsd-questions@freebsd.org, freebsd-geom@freebsd.org Subject: Re: geom - help ... Message-ID: <20060921093038.57966.qmail@web30303.mail.mud.yahoo.com> In-Reply-To: <45122531.6010503@infracaninophile.co.uk>
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--- Matthew Seaman <m.seaman@infracaninophile.co.uk> wrote: > Marc G. Fournier wrote: > > > > So, again, if I'm reading through things correctly, I'll have to do > > something like: > > > > gstripe st1 da1 da2 > > gstripe st2 da3 da4 > > gmirror drive st1 st2 > > newfs drive > > That's the wrong way round, I think. If you lose a drive, then you've > the whole of one of your stripes and have no resilience. Shouldn't you > rather stripe the mirrors: > > gmirror gm0 da1 da2 > gmirror gm1 da3 da4 > gstripe gs0 gm0 gm1 > newfs gs0 > > This way if you lose a drive then only one of your gmirrors loses > resilience and the other half of your disk space is unaffected. > Yup! In the case M(S(a,b),S(c,d)) the content on 'a' and 'c' and on 'b' and 'd' would be identical, so that the u had to do it handish and efficient or automatically and inefficient in case of a disk failure. I personally put the boot-stuff on a gmirror (no striping). So u might want to use something like this: M(a1,c1) for / S(b1,d1) for /not-so-important S(M(a2,c2),M(b2,d2)) for /usr/home By the way: A correct syntax would be gmirror label -b load gm0 da1s1a da3s1a gmirror label -b load gm1 da1s2d da3s2d gmirror label -b load gm2 da2s2d da4s2d gstripe label -s 65536 gs0 da2s1d da4s1d gstripe label -s 65536 gs1 mirror/gm1 mirror/gm2 Oh! And I am experimenting with my geom_raid5 implementation... But it is quite slow in write to UFS (but non-concurrrent write to raw-device is quite fast already). U can download it here (but it is quite difficult to integrate - many files have to be changed handish): http://home.tiscali.de/cmdr_faako/geom_raid5.tbz :-) -A __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
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