Date: Mon, 11 Oct 2004 00:25:46 +0200 From: Christian Hiris <4711@chello.at> To: freebsd-current@freebsd.org Cc: Chris Elsworth <chris@shagged.org> Subject: Re: RAID1 with gmirror Message-ID: <200410110026.03777.4711@chello.at> In-Reply-To: <20041010165852.GA15854@shagged.org> References: <20041010110159.GA91160@pcs28.suedfactoring.de> <200410101522.45548.4711@chello.at> <20041010165852.GA15854@shagged.org>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Sunday 10 October 2004 18:58, Chris Elsworth wrote: > On Sun, Oct 10, 2004 at 03:22:28PM +0200, Christian Hiris wrote: > > # gmirror configure -v -b load mirror0 ad0 > ^^^^^^^^^ > label? Yes, that should read "label" - sorry! > I'm quite interested that you didn't bother re-labelling the new > mirror device? I always thought that you had to (and I have been doing > this): No, re-labeling wasn't necessary. gmirror could read the existing labels and created the corresponding mirror*s** devices showed up under /dev/mirror/. fsck also went fine. I think this should work, as gmirror stores it's metadata in the last sector of it's providers. > 4) bsdlabel -e ad0 [taking into account the new 16 byte offset] I never read about the new offset - until now I had no time to study the gmirror code. Where did you find this interresting information? > Is this all completely unnecessary? The first few times I played with > gmirror, I was doing something similar to your method, but if you do > bsdlabel -r /dev/mirror/mirror0s1 (or whatever) on your setup, don't > you get warnings about partition sizes? Yes, I get those warnings, too - but I decided to leave the labels as is, because on a test array I found this working w/o any datacorruption. An example in 'man gmirror' describes how to set up a gmirror array on a disk with valid data. It uses 'gmirror lable' w/o extra labeling. I understand it the way that the term 'valid data' means 'existing (non-gmirror-)data on an already (before-gmirror-)labeled disk'. Maybe my understanding is wrong and you gave me the hint to the reason why my mirrors break on startup. I will do some testing on this. The 2nd reason why I didn't touch my old labels, is that I want to be able to step back to ataraid as simple as possible, just in case of a breakage of the gmirror code. > That's what worried me enough > to go through all the rigmarole above, which fixes those warnings. I use gmirror since the day before yesterday, so for now there are still some things that I couldn't test and possibly I overlooked some things. At a first look, my experiences were not so bad, I lost no data and gained a lot of flexibility in my hdd subsystem. - -- Christian Hiris <4711@chello.at> | OpenPGP KeyID 0x3BCA53BE OpenPGP-Key at hkp://wwwkeys.eu.pgp.net and http://pgp.mit.edu -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (FreeBSD) iD8DBQFBabb709WjGjvKU74RAjzIAJ4p+4RUbBgYLGeJlQX/GxXrvR1dswCdFOSy K5fuNpfvidRxvSEYVRYAYOY= =gXBY -----END PGP SIGNATURE-----
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