Create GMIRROR only one slice

[krad]

2010/3/29 Дмитрий Бехтерев <dbehterev at gmail.com>

> ---------- Пересланное сообщение ----------
> От кого: Дмитрий Бехтерев <dbehterev at gmail.com>
> Дата: 25 марта 2010 г. 19:03
> Тема: Create GMIRROR only one slice
> Кому: freebsd-geom at freebsd.org
>
>
> Hello all!
> I have problem with creating GMIRROR on select slice. So, I have two slice:
> ls /dev | grep ad4
> ad4
> ad4s1
> ad4s1a
> ad4s1b
> ad4s1c
> ad4s2
> ad4s2p1
>
> fdisk /dev/ad4
> ...
> The data for partition 1 is:
> sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
>    start 63, size 29350692 (14331 Meg), flag 80 (active)
>    beg: cyl 0/ head 1/ sector 1;
>    end: cyl 1023/ head 254/ sector 63
> The data for partition 2 is:
> sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
>    start 29350755, size 595786590 (290911 Meg), flag 0
>    beg: cyl 1023/ head 255/ sector 63;
>    end: cyl 1023/ head 254/ sector 63
> The data for partition 3 is:
> <UNUSED>
> The data for partition 4 is:
> <UNUSED>
>
> On first slice I created ufs slice and on second - ZFS pool (I build it
> with
> glabel):
> mount
> /dev/ad4s1a on / (ufs, local)
> devfs on /dev (devfs, local)
> tank on /tank (zfs, local)
> tank/usr on /usr (zfs, local)
> ...
> tank/var on /var (zfs, local)
>
> glabel list
> Geom name: ad4s2p1
> ...
>
> I want GMIRROR'ing /dev/ad4s1:
> gmirror label -v -b round-robin gm0 /dev/ad4s1
> but I get error "Operation not permitted" (although I set sysctl
> kern.geom.debugflags=16).
> MY OS: FreeBSD 7.3 Stable.
> What should I do to do this?
> Thanks all.
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>

Dont boot into the os, create the gmirror from the fixit mode of a cd, or
build a usb stick with freebsd on. You will need to newfs the gmirror device
after that so backup the data currently on /, then copy it back afterwards.

I have to ask, as you are using zfs why not just do a zfs root? If you do
decide to go for this option, use gpart to create gpt layouts, as you wont
run into partition size limitations if you upgrade the drives to big ones in
the future