Date: Thu, 27 Jan 2005 08:08:56 -0600 From: Karl Denninger <karl@denninger.net> To: Pawel Jakub Dawidek <pjd@FreeBSD.org> Cc: freebsd-geom@FreeBSD.org Subject: Re: Gmirror question - what am I doing wrong? Message-ID: <20050127080856.B45818@Denninger.Net> In-Reply-To: <20050127091905.GN795@darkness.comp.waw.pl>; from Pawel Jakub Dawidek on Thu, Jan 27, 2005 at 10:19:05AM %2B0100 References: <20050127000529.B40650@Denninger.Net> <20050127091905.GN795@darkness.comp.waw.pl>
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On Thu, Jan 27, 2005 at 10:19:05AM +0100, Pawel Jakub Dawidek wrote: > On Thu, Jan 27, 2005 at 12:05:29AM -0600, Karl Denninger wrote: > +> Now here's the problem. > +> > +> Let's say that I have the system sync'd with the larger and smaller block > +> count disks online. The SMALLER one fails. I replace it, but the other > +> larger disk is not available, because its in the vault. I thus replace the > +> disk with the SMALLER one, but I can't attach the slice on the replacement > +> disk, because that disk has a smaller capacity than the only remaining > +> active mirror component, and I can't make a slice bigger than the number > +> of actual blocks that exist on the drive! > +> > +> I'm screwed, and have no way out of this other than to ditch the entire > +> scheme, manually recreate the smaller volume, copy all the data over, and > +> restart gmirror from scratch. > > I need exact commands you use to perform this. > I did small simulation of your problem (if I understand it right): > > I created three md(4) devices: > > md0 - 12MB > md1 - 10MB > md2 - 10MB > > Now, I create a mirror from two of them: > > # gmirror label foo /dev/md[01] > > My mirror size is 10MB-512B. > Now I remove smaller component: > > # gmirror remove foo md1 > > And insert the second smaller component: > > # gmirror insert foo md2 > > Everything works for me. > > Some more notes: When you create a mirror, gmirror takes the smallest > component's size as a size of the whole mirror, so you should be able > to insert new components which are bigger than or equal to the smallest > one (used for mirror creation). Ok, I'll go through it again with the real disks and see what I get. I attempted this and it failed, but I may have inadvertently destroyed the metadata somewhere along the line. Let me see if I can recreate it again, and get the exact command sequence. -- -- Karl Denninger (karl@denninger.net) Internet Consultant & Kids Rights Activist http://www.denninger.net My home on the net - links to everything I do! http://scubaforum.org Your UNCENSORED place to talk about DIVING! http://www.spamcuda.net SPAM FREE mailboxes - FREE FOR A LIMITED TIME! http://genesis3.blogspot.com Musings Of A Sentient Mind
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