Mirroring: gvinum or gmirror?
efinleywork at efinley.com
Thu Aug 31 19:31:00 UTC 2006
----- Original Message -----
From: "David Robillard" <david.robillard at gmail.com>
To: "Elliot Finley" <efinleywork at efinley.com>
Cc: "Jonathan McKeown" <jonathan at hst.org.za>; "FreeBSD Questions Mailing
List" <freebsd-questions at freebsd.org>
Sent: Thursday, August 31, 2006 12:08 PM
Subject: Re: Mirroring: gvinum or gmirror?
> On 8/31/06, Elliot Finley <efinleywork at efinley.com> wrote:
> >> ad0: 4112MB <WDC AC24300L 09.09M08> at ata0-master UDMA33
> >> ad3: 4028MB <Maxtor 84320D4 NAVXAA21> at ata1-slave UDMA33
> > > Then make sure you install FreeBSD on the bigger one (i.e. here that
> > > would be ad0) then setup gmirror. If you do the oposite, you will have
> > > a "Consumers too small" error when you try to bring the mirror
> > > together.
> > I could be wrong, but that seems backwards.
> I know, that's also what I thought before I had the problem. (hence
> the Tip of Day!)
> It's quite easy to understand when you think about it. Let's say we
> have the same disk drives as above in which ad0 is bigger then ad3.
> So you install the OS on the smaller ad3 disk first. Then you setup
> gmirror on the bigger disk ad0. You then dump(8) the OS from ad3 onto
> the broken mirror gm0 which is made up of ad0. Next you reboot on gm0
> (hence on ad0). You clear ad3 which is not used anymore and try to
> `sudo gmirror insert gm0 /dev/ad3` = WRONG!
Well yes, if you do it this way, you are correct. Why not just install the
OS on the smaller drive, skip the dump step and just use the installed drive
as the first drive in your mirror. That's how I've been doing it and it
I've got a write-up of the steps required to do this if you or anyone else
needs them. I also routinely disconnect one of the drives in my mirror
before a major upgrade to the OS or ports so that if I mess it up, I can
boot back to the previous state. I have a write-up of the steps needed to
do this remotely over ssh (again, if you or anyone else needs them).
More information about the freebsd-questions